I'll reserve this for codes. I am really not sure where I am going with this at this stage - it may get dark/hit on some fetishes.
I am very much inspired by Tiffy from "Raw Time"
https://www.youtube.com/watch?v=7vBrLy-C3LM
My Sister the Lab Rat
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EddieDavidson
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My Sister the Lab Rat
Last edited by EddieDavidson on Fri Mar 21, 2025 9:47 pm, edited 1 time in total.
All of my stories: https://storiesonline.net/a/eddie-davidson
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The site is free up to 100 chapters a day. You can get unlimited just for submitting stories.
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EddieDavidson
- Posts: 390
- Joined: Fri Jun 23, 2023 2:38 pm
- Has thanked: 29 times
- Been thanked: 337 times
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Chapter One
"Congrats on winning the science thingy, Scro." My sister shoved my door open without knocking, stepping inside like it was her room. She immediately scowled as she assessed my bookshelves, test tubes, science fiction posters, and action figures and found them lacking in “cool”.
Tiffy stood there in all black, arms crossed, heels clicking against my floor. She almost never knocked on my door, but fortunately, she rarely ever talked to me – much less visited me. She’d been in her “rebellious” goth phase for as long as I could remember—not that anyone in the house cared enough to rebel against.
"That 'science thingy,' as you call it, is the Regeneron Science Talent Search," I said, leveling a look at Tiffy. "It required over 800 hours of research, a formal research paper, and surviving multiple rounds of scrutiny by PhD-level scientists. I had to meet strict pre-requisites, including original, independent research at a near-college level."
I folded my arms. "It culminated in a full-scale project presentation judged against some of the brightest high school minds in the country—future physicists, medical researchers, AI pioneers. And it earned me a finalist spot, which, by the way, comes with scholarships and a shot at meeting Nobel Prize winners.”
“Whatever,” she stood there as if waiting for me to say something else – or trying to make up her mind about something. She was wearing a skimpy outfit; despite being heavy-set. My sister has a pretty face, but she’s quite sensitive about her weight. She pretends it doesn’t bother her, but if you even imply that she’s fat, she can be quite vengeful.
“What do you want, Tiffy?” I sighed as I closed my dog-eared copy of Solaris by Stanisław Lem. It was one of my favorite science fiction books. It’s about a psychologist named Kris Kelvin that is sent to a space station orbiting the mysterious planet Solaris. When he arrives, he discovers a sentient planet that is incomprehensible; it’s an intelligence so alien it either refuses to communicate or simply doesn’t see the point.
My sister would identify with Solaris. She didn’t do small talk, didn’t explain herself, and didn’t care if anyone understood her. She existed in her own world, reacting on some logic the rest of us weren’t privy to. And that made me Kris Kelvin—stuck in close proximity, trying not to set off something I barely understood.
“Do I have to want something to come and tell you that I am proud of you?” Tiffy replied coyly. I didn’t buy her nice act for a second. “Did your Regeneron thingy come with any prize money?”
“Even if it did, I’d give it to Mom and Dad, and not you,” I crossed my arms, and sat cross legged on my bed – my body language made it clear that I wasn’t interested in conversing with her.
“Don’t get your undies all in a bunch, Dalton. I am not asking you for money. I just wanted to find out what science project you would work on next. If you win money, you could hire a person to help you test out your theories or whatever.”
“I didn’t win any money, and I don’t need a human lab rat,” I scoffed at the very idea of doing human trials on a person.
I didn’t expect my sister’s expression to brighten, but it did. Tiffy had a lovely smile – the kind that could brighten any room. It was unfortunate she almost never allowed anyone to see it. The times I remember seeing her smile were when I fell off my bike and skinned my knee or when my mom accidentally dropped my birthday cake on the floor. I recall she smiled toward the end of the Titanic when the mom locks the door after realizing she can’t escape before the boat sinks.
“Why does that amuse you?” I asked.
“I like the term human lab rat; that’s kind of cool. I was going to ask if I could be your specimen or whatever, and help you test out your theories. I am not book smart like you, so I probably couldn’t be a lab helper, but I could volunteer to do tests and stuff.”
I was taken aback by my sister’s strange request. She never did anything for me. She never lifted a finger around the house to help my mother clean or do chores. She barely did her own homework, and my guess was this was some sort of elaborate trap.
"Why would you do that?" I asked.
"I don't know," Tiffy said with a shrug, her tone flat. She was lying. My sister never did anything without a reason. It was like her to be aloof and detached. “I was hoping to earn some money,” she corrected when she realized that I was not buying it.
“Well, I didn’t earn any money,” I shrugged dismissively as I picked up my book and re-opened it. I was hoping that would be a polite signal that she should leave my room. My room was my domain – the place I spent most of my time. it was a treasure trove of my favorite things - computers, video games, television, books, action figures, test tubes, electronic kits, all the nerdy stuff that I had. I loved being alone and solitary, and in that sense – my sister and I were alike.
“If I agreed to become your lab rat, would you stand a chance of earning money on your next science experiment?” she asked – clearly fishing for an opportunity but still trying to sound ambivalent.
“You don’t even know what I am going to research next, why would you offer to be a test subject?” I was puzzled, but I didn’t wait for a response before changing my question. “Why would you want to hang out with me? You don’t like me.”
My sister seemed uncertain of how to respond to that. She could have said something about us both growing up and moving away with a chance of starting new lives and seldom seeing each other. She could have said we live in the same house but seldom leave our rooms and how we should get to know one another.
“That’s fair,” she shrugged. “I can come across like a bit of a bitch.”
“Come across LIKE one?” I laughed at the thought. “You aren’t LIKE a bitch. You ARE a bitch if there ever was one. You stormed into my room as if you owned it and then called me a scrotum while minimizing my accomplishments.”
“Sorry,” she seemed contrite, unsure of herself, and that was odd. I had never seen my sister be vulnerable before. “Well, what are you going to research? I would like to help if I can.”
“I really don’t know,” I answered truthfully. “I poured so much time into my last project that I haven’t thought about it. The field of science is vast, and I have interest in everything from physics, genetics, AI, and chemistry to medicine. The first step for me would be to do random experiments and see what inspires me. I doubt any of that would interest you.”
“Do you think you could make me thinner?” she asked – it wasn’t sarcasm, and it came across as an authentic request for help. I could have been snarky, but I felt like she may be genuinely looking for help or a shortcut to better health.
“A good diet, willpower, exercise, and some nutritional supplements could do that. If you want me to put something together for you, I will,” I offered.
“I’ve tried diets, and I hate exercise. Do you think maybe you could give me a pill or a shot that would make me thinner and hotter?”
I was no psychologist like Kris Kelvin, but it didn’t take a degree in psychology to recognize that my sister had low self-esteem and a poor self-image and wanted some magical panacea that would make her a different person – or at least outwardly so. I hadn’t really thought about it before, but part of why she could be such an insufferable asshole and lashed out at people was probably insecurity.
“Science doesn’t work like that, Tiffy. I can’t experiment on a person and just make them lose weight. It would take years to develop something, and it would never start with human trials. It could cause harm or have unexpected side effects.”
“I don’t care about that, and I’d sign whatever waiver you want – maybe you could make me taller, prettier, or smarter. It doesn’t have to be thinner.”
I shook my head. I could have said she was pretty and intelligent. I felt like she might be fishing for compliments. I’ve seen what happens when my parents tell her she’s pretty. She scowls and doubles down on self-deprecation. I also knew that she read a lot of Goth books and was intelligent when it came to subjects that interested her.
“Look, give me pumpkin-sized titties, and I’ll do whatever you want,” she insisted stubbornly, shifting her weight to her hip and folding her arms.
I chuckled. “I can’t do surgical boob jobs, and that would require me to not only see your tits but to actually touch them. I am your brother!”
“That’s why I trust you,” my sister popped her top open quickly to reveal her milky white tits. They were fat and chubby and hung down, but still remarkable to me. “There -you saw them. So, we have that out of the way. I am not asking you to do surgery unless you think that’s the only way. Give me a pill or something and make them look natural but not so saggy and ugly.”
“The sag is hot, and you’ve got some huge strawberry nipples,” I blurted out without thinking about how that sounded. I stopped myself, but it was too late, and I blushed. I loved porn almost as much as I loved science, and even my sister’s natural tits were a welcome sight – despite the guilt I felt about staring at them.
“It’s science, so it wouldn’t be sexual, but you can grab them, touch them, squeeze them, whatever. I’d be your lab rat. As long as we can keep it between us, whatever happens in your room is just science.”
I arched an eyebrow. I would have been surprised that my sister wanted to have a discussion of any length with me. I was absolutely floored that not only did she want to talk to me, but she offered to help me with my science projects. I could hardly accept that she took her tits out in front of me like it wasn’t a big deal and continued to stand in front of me like that.
I assumed all of this was some bizarre attempt to trick or demean me – or use me to her own ends. It just seemed a bit too strange to be true. The concept of Occam’s razor “The simplest answer is probably the truth” doesn’t work on my sister because she often defies my understanding of logical thinking.
I could have just shot her down and been done with it and that would have been the safest thing to do. However, I was curious about her motivations and bored enough to continue the discussion as long as it remained hypothetical. If I am being honest, I wanted to keep looking at my sister’s tits, but despite that I looked away from them when I asked my next question.
"What if I’m not interested in altering the composition of your body? What if I’d rather explore other types of science? For instance," I leaned back, tapping my chin, "a sensory deprivation study. I could test how long you last in complete darkness and silence before your brain starts hallucinating."
Tiffy narrowed her eyes. "You want to lock me in a closet and see if I start talking to ghosts? I would have always been down to do that."
I realized that I hadn’t quite made my point. My sister did love darkness, and I assumed she was being a bit facetious. I glanced at her boobs, making mental snapshots because I assumed she’d leave after I asked my next question.
“As I told you earlier, I have many areas of interest, and I’d probably want to perform a wide range of exploratory experiments before settling on one project. You seem focused on helping me because I might be able to help you alter something about you. What if I’d rather explore other types of science? For instance," I said, flipping through my notes, "a study on nerve response and pain tolerance. We could see how different temperatures affect pain perception. Ice baths, heat exposure, maybe even a mild electrical impulse—"
“Would you eventually get around to making me learn to get off from pain or something?”
Tiffy seemed receptive, almost excited by the proposal. I assumed she just didn’t understand the repercussions of what I was telling her.
“No, If you were truly my lab rat, your happiness would not be my concern unless I were trying to measure the relative manner in which you process pleasure. Which I suppose I could do, but we are brother and sister – and I am not talking about tapping your knee to test your reflex in that hypothetical. I might be testing how sudden blasts of cold air affect your nerve response. You'll sit here while I direct a controlled burst from my modified air compressor at you – and then measure whether or not the cold air could make your nipples hard -or even the sight of the compressor.”
“Cool, sure,” she shrugged.
“It wouldn’t result in weight loss, increased intelligence or height, or even bigger boobs – at best, it could be mild stimulation for you, and at worst, it could cause frost burn. Would you really agree to that if it didn’t benefit you directly?”
“Why are you trying to talk me out of helping you? If the tables were turned, and you came to me and told me you’d do whatever I want, I’d use you as a human ashtray and flick my butts into your mouth while I sat my fat ass on your back and used you as a human chair,” my sister painted a devious mental image for me.
The degrading position she’d put me in sounded like classic Tiffy. She’d always been a bit of a bully to me when we were little – calling me pencil dick and nerd.
“I wouldn’t come to you and volunteer for that; are you going to allow me to set up an experiment where I use you like a lab chair?” I joked.
“I told you that I am down for anything, and I’ll be your lab rat.” If that’s part of the experiment, then I am there for it, Dalton.”
I didn’t expect her to sound so sincere or to answer my question. I assumed she knew that I was joking. I was taken aback and remained silent as I tapped my pen.
“Fine, I’ll go find some other way to kill time,” my sister started to button her top and leave.
“I was thinking, Tiffy.” I held up my hand. “It’s not every day that we talk, and I didn’t expect this or ask you to show me your boobs. Are you really willing to do ANYTHING I say and allow ANY experiment? Have you given any thought to the repercussions of that? What if I chose to use it as a human Petri dish and incubated the flu to study its effects on you? Or did I decide to chop you up into little bits?”
I assumed that my sister would surely see the folly of her request, and so I glanced up fully at her boobs so that I could take one last long look before she left in a huff.
“The fact that you are concerned enough about me to worry about stuff like that tells me that you aren’t a mad scientist and a psychopath, Dalton. Anyway, If you were to do something like cut off my tongue and sew it to my asshole so that I have to lick my shit when it comes and taste it – don’t you think you would get in trouble? So, do I really need to spell things out like that?”
“I have a hard time understanding why you are willing to write a blank check with no parameters or boundaries defined without a promise that I can play the Wizard of Oz and give you a brain and boobs like the Goth version of Dorothy,” I replied.
My sister found that amusing, and she snickered – lighting up the room again and acknowledging my point. “The fact that you didn’t just tell me whatever I wanted to hear in order to get me to be your Lab rat means that I can trust you -I know there are no guarantees that whatever your research would benefit me.”
That was pragmatic and a compliment. I acknowledged and thanked her while I gave it some thought. “What prompted you to come here today? Was there something that happened?”
Tiffy made a derisive ‘pshaw’ noise with her mouth when I asked the question and told me that I was the smartest person that she knew. “I’ll never be that smart, but maybe I can contribute to your research, and why are you making me beg?”
“I am not asking you to beg. If you want to be my lab assistant, then you would have to be interviewed. I think understanding your motivation for the job would be a reasonable thing to ask,” I countered.
My sister didn’t like it when I said lab assistant. “Who said anything about assisting you? you can test stuff on me, but I am not going to organize your books and dust your shelves or something.”
“You said you’d do anything I say, and then you said there would be no boundaries or limitations, and now you are telling me what you won’t do,” I found that to be classic Tiffy – a contradictory offer.
“For a smart guy, you really are dumb,” she frowned. “Okay, I’d be your lab assistant as well, but if you want to know my limits, then I get Friday and Saturday nights off,” she said firmly – like it was not negotiable.
Now we were getting somewhere – I could entertain a reasonable offer of assistance. The open-ended one sounded too unrealistic, and somewhere along the way, she’d get pissed off and quit when I pushed the wrong button or framed things the wrong way.
“What time does that begin?” I asked for clarity on her working hours.
“Night,” she insisted in a patronizing way. “You know? When the sun goes down and it gets dark out? I am a creature of the night – so I can do whatever I want from sundown to sunrise on Friday and Saturday – any other time I do what you tell me.”
I arched an eyebrow – intrigued. “Any other boundaries?”
“I am not going to stop smoking cigarettes or cloves, drinking, or doing drugs,” she said firmly.
“What if I require it of you for an experiment?” I fired back. I didn’t approve of any of those things, and I knew our parents didn’t either. I presumed that my sister didn’t shoot up heroin or do hard drugs of any kind, but it wouldn’t have surprised me if she frequently smoked marijuana.
“You asked for my limits, and now you are telling me that I can’t have any limits?” my sister tried to turn my logic back on me and make it sound like I had made two mutually exclusive statements.
“I may decide to limit or completely stop any of those activities, as I will be providing you with a special diet and exercise regimen to reduce your weight,” I instinctively replied. I didn’t give that particular offer much thought. I happily performed a Google search for my sister to help her before we started talking about being my lab assistant/test specimen.
I was surprised that she stopped slouching and smiled at me broadly – quite pleased. “That would be cool! So, you are saying I got the job?”
“Do you have any other limitations or boundaries as a test subject or assistant?”
“Don’t transform me into a normie has-been or an insufferable Bimbo Barbie doll,” she replied without hesitation.
I liked the word “transform,” and I kind of keyed in on that – it inspired some wheels to start turning in my head. I had some idea of a Barbie Doll – a blonde, vapid, narcissistic bimbo that thinks only of themselves and shallow thoughts. I asked her what a normie has-been was.
“Normal,” she shrugged. “Don’t try to turn me into Tina Turd the Nerd,” she explained. “I don’t want to be a science geek and stop dying my hair blonde or look boring and act boring. That’s why I don’t want to be your assistant. I don’t want to measure beakers and talk about “The Structure of Scientific Revolutions,” she pointed to a prominent book title on one of my shelves. “I am not going to study science and be turned into a super brain.”
“Didn’t you tell me you want to be intelligent?” I asked. I had no intention of turning my sister into anything she didn’t want to be, and I had no delusion that I had the capability to transform her into anything – much less a super brain. However, her request puzzled me. If she truly thought I could enlighten her – why wouldn’t she want that gift of superior intellect?
“I don’t mind if you experiment on me with hypnosis or mind control or something, but I don’t want to be turned into someone boring. If you are going to make me into something, turn me into a super slut, or someone interesting. I can be boring on my own.”
Wow, that was quite a revelation. Arching an eyebrow, I could hardly express how intrigued I was by what she said.
“You’ll allow me to alter your self-perception and implant suggestive behaviors as long as those behaviors meet your approval, is that it? I can’t make you a better student, or do you want to do chores around the house? Create a Tiffy 2.0?”
I have to admit that while I doubted I had the ability to implant suggestions, I enjoyed the hypothetical prospect that I could improve my sister.
“Tiffy 2.0 sounds awesome,” she concluded. “I don’t really want to be a maid or a better student, but I am not going to say no. Can I ask that if you hypnotize me, it’s where I don’t actually remember it while I am under? Chores are fucking death!” she frowned dramatically over how boring and tedious that was.
“As my Lab assistant, I would require you to clean my room, sort and organize daily except on Friday and Saturday night, whether I can successfully hypnotize you or not, are you sure you would want that job? Alphabetize my books, bring my laundry to the bin, fold it, and help me set up and record experiments?”
My sister gave it only a moment of thought before shrugging. She didn’t seem enthusiastic. “I will do whatever you tell me, but I am probably going to complain about it,” she promised.
“What if I forbid you from complaining and insist that you address me with respect?” I asked. I was unconvinced that my sister would stick with her offer after the first time that I asked her to do something she found boring.
“You’d have to make respect you,” she replied – staring me right in the eyes. My eyes flicked up from her bare nipples and locked with hers. I could tell that she was waiting for me to ask her how to make her respect her, and I didn’t take the bait.
“You aren’t providing much incentive for me to want to offer you the job. If this were an interview and you promised a leading researcher that you were going to be a curmudgeon that complains, do you think you’d get the job?”
“As a lab rat? Why is it so important what I think of you, anyway?” she asked. “Do lab rats have to be nice to the Researcher?”
She had a point. “Researchers use a combination of positive and negative rewards to get the behavior they desire from their lab rats. I may decide to grant you a special dessert if you have performed adequately that day, or I might require you to stand in the corner of my room when you first enter if you are a bitch, until your behavior improved.”
My sister barely reacted. I expected her to cringe or refuse, but instead, she nodded in agreement that would be acceptable. I expected her usual sarcasm, but instead, she just looked at me, waiting.
I tapped my pen against my notebook. "Alright. First, baseline data collection."
She nodded. "Tell me what to do."
“Remove all of your clothing, everything – shoes, hair clips, earrings – all of it.”
My sister began to undress right in front of me – no modesty, no shame. She went for it. I wondered if she had expected it. I would have expected some reluctance. I picked up my notebook and began to journal her behavior in my lab shorthand – so that in case she read it, she would not fully understand what I wrote.
“Don’t tell Mom and Dad that I am your lab rat,” my sister said as she rolled her panties down her thighs – revealing her fat, hairy pussy.
“I would tell them you are my lab assistant – helping me with my research if they need to know. I won’t keep secrets from them, but I won’t advertise it either. It’s possible they will want to enter my room during our research.”
“Do they ever come into your room now?” my sister stopped undressing for a second and gave me a knowing look. “They don’t come into my room either. Lab assistant is fine but tell them you are paying me. They won’t believe I am doing this for free,” she advised.
“I am the one who gives instructions,” I replied and added that I wanted her to remove her chewing gum. My sister didn’t think that I had noticed her quietly chewing the gum. She took it out and handed it to me – it was still wet with her saliva. I put it in a napkin, but I was tempted to put it on her nose like an angry schoolteacher.
“Stand up straight, shoulder’s back. Hands above your head, palms flat on the top of your head, legs apart, I want to measure you,” I removed a ruler and protractor from my desk. The metal protractor looked intimidating and had a sharp point.
[[[ image 01_titty.jpg goes here centered ]]]
My sister complied as I studiously measured her from every angle. I didn’t just measure height. I measured the distance of her ankles to her toes and the length of her collarbone and neck. I tried to pretend that seeing her naked didn’t affect me, but it did. I could smell her body – the sweat, the faint scent of her pussy and I noticed tiny things like how her skin reacted with goose bumps to the slightest touch.
My initial measurements were very innocent but quite thorough.
“Are you going to measure the circumference of my nipples with that pointy thing?” Tiffy asked as she nodded at the stainless-steel protractor that I had left on the desk in front of her while I used the ruler.
“Yes, I am getting to the more intimate parts of your body,” I tried not to stammer nervously. I measured the tip of her nipple to the base- avoiding touching it directly. I liked how stubby and fat it was. “I am going to have to think of a specimen name for you. Tiffy is too personal; when you are Tiffy, you are allowed modesty. As a specimen, you do not have privacy, and I will need to be free to touch you anywhere.”
“What’s my name?” my sister didn’t argue or balk – she accepted it. When I gently touched her nipple, I expected a slap, but it didn’t come. I used the protractor to carefully measure the distance around her nipples and found that they were each slightly different. I also measured how one was longer than the other.
I didn’t answer right away because I hadn’t thought about it. I wanted it to be something ominous or cool. I was trying not to let on that I was flummoxed by my sister’s nudity – it was so distracting, and I had to stand behind her while I adjusted the erection in my pants.
“Your name is Gothopotamus,” I quipped, testing to see what she’d say to that. I stood behind her and watched her clench her ass cheeks angrily. I don’t know why it amused me to see her frustrated and not say anything to me – but it did.
“No, that’s quite right, it’s too long. Specimen XXL – or 2XL?” I scratched my chin as I squatted down, eye level with her hairy pussy. “What do you think of that?”
“Do you have to tease me about how chubby I am?” she asked – pouting and vulnerable.
“I’ve seen how you react to our parents praising you and saying you are pretty – you tend to yell at them and dismiss it,” I explained.
“I know I am not a beauty, and I don’t want to be patronized. That would be like me calling you muscular, Dalton,” she explained. My sister was pretty – and I assumed she knew it. It seemed illogical for her to refuse to accept it as far as I was concerned.
I decided to take bold action, and I placed my hand between her thighs – and stared up at her. I waited for my sister to look down her nose at me and tell me that I was going too far. She had to know my next move was to touch her pussy. I waited for the scolding that never came.
“What are you measuring down there? the circumference of my fat asshole? Or the shadow that my slit makes on the carpet?” she chuckled. It was so crass and vulgar – that I nearly shot a load in my pants.
“Patience,” I insisted that my sister stop rushing me. I was trying to get the courage to go a little further with my examination, and I didn’t want to tell her that – so I acted like it was intentional that I was making her wait.
“is that my Specimen name?” she asked – a trace of excitement in her voice. I wondered if she thought I was being audacious.
“Yes, because you lack it, and by the end of your term as my lab rat, you’ll have had to develop it,” I declared. It wasn’t the ideal name because it was longer than Tiffy – but I liked it.
“At least it’s not Tina. You can call me anything you want except that,” She decided.
“I will make a note of it on your list of do’s and don’ts as my specimen, but my question is, will you answer to it, Patience?” I asked as I slid my finger up to her pussy – delicately and ever so slightly parting her pussy lips so that I could try to measure the gap with my ruler.
“Yes,” she swallowed quietly. I liked where this was going, and much to my chagrin, I felt moisture on my sister’s pussy lips. I had never touched a woman’s pussy, and while I knew that girls got wet – I wasn’t sure what to expect.
“Sorry about that,” Tiffy politely apologized – clearly aware of what I was doing and how she was physically reacting to my touch.
“It’s perfectly natural, Patience. Your body is simply reacting to physical stimuli. The autonomic nervous system doesn’t distinguish between intentional sexual contact and other forms of sensory input—it only processes pressure, temperature, and nerve activation. Tactile stimulation, particularly in areas with a high concentration of mechanoreceptors, can trigger increased blood flow due to vasodilation. The parasympathetic nervous system mediates this response, preparing the body for potential activity, even when the stimulus lacks sexual intent.”
I touched her even more lightly, measuring taint – distance from asshole to pussy without actually spreading my sister’s tightly clenched butt cheeks. I wanted to see that part of her, but I was a bit too timid to dare that until I finished measuring her pussy.
“Additionally, the skin contains Pacinian and Meissner corpuscles—nerve endings that respond to deep and light touch, respectively. Depending on location and sensitivity, their activation can send afferent signals to the brain, which may be misinterpreted as arousal. This is why certain medical exams, massages, or even accidental pressure can elicit similar responses. It’s an entirely physiological reaction, independent of conscious desire,” I said as I carefully measured her – careful not to pull her labia, touch her clit, or clitoral hood.
“Please tell me this is not the first pussy that you’ve ever touched, Dalton?” my sister sounded incredibly disappointed to the point of frustration.
“No, of course not,” I lied. I’d never come close to going this far with a girl. I wouldn’t have known the first thing to say to one in order to coerce her to let me kiss her – much less get this far.
“Whose twat have you played with?” she asked.
“I am not playing with it, Patience!”
“Trust me, I know – you are acting like its liver on your plate and you are grossed out by it. It’s humiliating – do I stink or something?” she asked – scrunching her nose and looking mortified.
“I was trying not to overly stimulate you,” I assured her, blushing myself.
“Mission accomplished,” she assured me that I was far from doing that – I noticed that her pussy was bone dry and no longer juicing up. I felt angry, exposed, and vulnerable -like I should lash out at her for exposing me as a fraud. I knew that I had no business touching my sister’s pussy. I was suddenly recognizing so many conflicting emotions – guilt that I had touched my sister, anger that she knew I was lying about my experience, frustration that I had no clue about women’s bodies.
“I am sorry that I am not masturbating you to orgasm, Patience! If you came here to get your rocks off, then you came to the wrong place. You asked to be my lab rat – the first step is to baseline you. I have no interest in finger fucking you – but once we pass the threshold where I insert a finger – there is no going back to normal.”
“I think we passed normally a long time ago, Dalton. I am sorry for being a bitch. I will hush and let you take a good, long look under my hood. I just haven’t had any dick for a while – and I am a little horny, and this is doing the opposite to me,” she grunted.
“How sexually active are you?” I asked as I adjusted my posture and measured the distance of my sister’s clitoral hood.
“Depends on what day it is,” she giggled before becoming serious. “A lot of girls and some guys think I am easy and fuck a lot, but the truth is that I am a fatty and don’t get as much action as people think. I dress a little slutty, but I haven’t had a regular boyfriend in months. I guess the last time I had actual sex was back then.”
Holy shit, I was rocked by my sister’s honesty. I couldn’t imagine a scenario in which my sister didn’t snarkily dismiss me if I had asked her who she was having sex with. My parents had never met any of her boyfriends- my sister always acted aloof and like she was a free agent who fucked anyone she fancied.
“I have a couple of girlfriends at school, I ate out Ophelia a few months ago when we were bored, but she didn’t reciprocate – so when you were whisper-touching my pussy like it was going to bite you and swallow you whole, I thought maybe I had genital warts or something weird. I don’t have genital warts, do I?”
I wouldn’t have been able to tell her even if I knew what they looked like. “I’d have to run blood tests,” I bluffed. I knew Ophelia – she was a hot brunette, very tall, and always looked aloof like she was angry at her dad. The thing that I noticed about Ophelia was that she seldom wore a bra to school, and she had saggy boobs that hung down in her tank top. Her nipples pointed down, and I often wondered why she didn’t wear a bra – assumed that she might not want to draw attention to them by not wearing a bra.
“What about oral sex?” I asked – still measuring.
“On you?” she scoffed.
“No, on whoever – do you give blowjobs to random guys at school or anything like that? charge money?”
“You think I am a whore?” my sister sounded incredulous. She was standing with her legs apart, naked, and allowing me to play with her pussy. I didn’t think the question was that far-fetched.
“As my lab specimen, you must answer all questions truthfully and fully, or else I will potentially collect invalid information. You seemed to want money when you first approached me about this job. If you are willing to do this – it wouldn’t be out of the question that you’d give head for money.”
“True,” my sister admitted and added that she didn’t do that. “Guys don’t just randomly walk up and whip out a hundred-dollar bill and ask for girls to go down on them.”
“I know that,” I said. “You hang out with some odd characters,” I referenced the goth kids at school who dyed their hair and pretended to be vampires while smoking behind the cafeteria. “It may be some kind of free-love/free-sex kind of thing.”
“Yeah, I am a free-use slut – I fuck anyone, anytime, anywhere,” she said with all sincerity.
“Really?” I asked – quite surprised. That sounded strangely enticing.
“No, but I am about to run out in the street and fuck the first guy walking down the street; can you please stop tugging my clit? You are teasing the fuck out of me, and getting me all fluster-fucking horny, Dalton,” she breathed in and out. I didn’t realize that my sister’s pussy had begun dripping again or that I had been non-stop tugging her clit for no apparent reason while I asked the questions – I must have become distracted by my own arousal.
“You’ll be regularly soaked, and I am going to tease you to the edge of orgasm. Are you already complaining?” I kept performing the same move. I was embarrassed that I had no real scientific reason for why I had done that and shocked that my sister let me get away with it for as long as she had.
“I told you that I would do what you told me, and I might complain, Dalton,” my sister started to pant, a panicked look on her face. “Are you sure…are you sure….are you sure...you want to make me….oh, oh, oh, please don’t, please, stop, it’s embarrassing, Dalton – Can I..” she brought one hand down to her pussy, to force my fingers away from her clit and masturbate herself to completion.
“No, you may not, Patience,” I slapped my older sister’s hand away and talked down to her like she was a petulant, naughty child. I kept frigging her – up and down, up and down.
“At least put a finger in me and press down on my clit; this is torture, Dalton, I wouldn’t jerk you off and keep you from cumming – I can’t take it.”
“You can take it, you will take it, and you aren’t allowed to cum without permission while you are my specimen,” I insisted and kept right on lifting her clit flap up and down. My sister started to wiggle and hop from foot to foot like she had ants on her legs and couldn’t slap them off.
“I can’t cum EVER without permission? Or just right now, like this?” she gasped in horror. She had returned the hand I slapped to the top of her head but removed the other and brought it to her breasts.
“Naughty Patience, keep your eyes straight ahead, shoulders back, and both palms flat on top of your fat head,” I frowned. I didn’t mean to call her fat – but I liked that my sister didn’t question my authority. She did as instructed.
I had never intended to forbid my sister from masturbating herself or having an orgasm. I simply meant that she could not cum right at that moment. I honestly had no idea what she would physically do when she came. My experience was limited to watching adult actresses’ fake orgasms on porn clips.
“Please, Dalton? You can’t be that cruel,” my sister couldn’t stop gyrating her hips, and her tummy quivered. She placed her other hand on top of my head and grabbed a bit of my brown hair.
“Hands off of my hair, slut!” I insisted. My sister had told me that I could call her anything except for Tina – I just tested that theory, and she didn’t slap me or tell me that was too far. I slapped her hand away from my head.
“Please, may I cum, Dalton? I am so close; I am ready to cum like this; just push down on my clit as if you hate me – I am sorry I can’t hold this position, I’ve never..oh…never…never..oh.”
I felt like my sister was giving me the joystick cheat codes on how to get her off – and it was working!
I was going to ask my sister if she really wanted to be my test subject after all. I had already asked her that question, but I felt like consent was key, and now that we had begun – maybe she was having second thoughts. However, her eyes rolled into the back of her head, and her toes curled up. Tiffy’s tongue fell out of her mouth, and she began to drip so much cream from her pussy that it was coming out like spit.
“Punish me if you want, but I can’t take it, fuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuck,” my sister grabbed my head and nearly pushed my face to her pussy to lick it, while fucking the air. She squatted and then laid down flat on my carpet while writhing and finger fucking herself. She rolled over on her stomach, and humped her finger, like she was fucking a man. I saw her tight ass cheeks flap open a few times, and her cute- round pink asshole. It was just for a split second.
I felt like my sister was showing me something that I wasn’t supposed to see – and now my cock hurt as it shifted uncomfortably in my pants. I was turned on but obviously not quite as much as my sister.
It took her a minute and forty-three seconds to achieve orgasm and then compose herself. I know because I measured it and imagined a diagram that I might create of the velocity and intensity of the orgasm relative to how completely uninhibited my sister became.
When she was finished, she looked up at me like she couldn’t believe what she had just done. “I am sorry about that, Dalton; I couldn’t hold out any longer. Did I pass the test?” she asked.
I had no idea what test she meant.
“It wasn’t a test; it was a baseline to see how long you could last,” I interpreted my sister’s question and added “There was no optimal score that you had to achieve.”
“It’s hard to understand you sometimes,” my sister admitted as she got to her knees and stood up. “It’s a simple yes or no, Dalton. Did I fuck up and get your finger all sticky and freak you out, or are we cool to keep doing this?”
It was hard to keep a flat expression on my face. I didn’t want to seem too eager, but my sister could probably see that I was struggling not to smile. “Yes, you did fine. I will expect you to hold out longer next time.”
“It’s going to suck not being able to cum anytime I want. On Friday and Saturday, I am probably going to fuck the banister on the stairs and go full freak-mode with my clit just because I can’t get any satisfaction whenever I want. I’ve never had anyone tell me that I can’t have an orgasm before – it sucked.”
I wanted to ask my sister if she still wanted to do this, but I didn’t get the chance. She had another question before I could respond.
“How does this work at school and stuff? I can still date, and have an orgasm with other people? I just can’t masturbate anymore?”
My sister had made these rules simply by asking me the questions – I had never dreamed she’d give me that sort of authority, or that she’d deserve that kind of structure. I hardly had any scientific rational for orgasm denial.
“I don’t know yet; I’m still in scientific exploratory mode,” I tried to be non-committal so that I could have some time to think about it. I expected that my sister would be rational and understand that we’d only just started this change in our relationship, and I needed time to ponder the ramifications of any new rule like that.
My sister isn’t rational.
She looked absolutely terrified when I failed to immediately give her a yes or no, so I decided to give her one.
“No, you may not date, and that includes casual sex for money or otherwise,” I decided to throw in a stipulation about my sister being a prostitute just to make it sound official. “I am not going to play with your twat to get you off anytime you want. If you want to have an orgasm outside of your examination time, you’ll ask permission and then I’ll tell you if you may have privacy.”
I waited for her to argue with me about that and when she stood there aghast, I continued.
“When and if I decide that you may date, I will revise the rules about sexual relief, and I may introduce a control group for you to mate with. However, I will first determine that you are on birth control.”
“I am already on birth control now,” my sister said before repeating some of my words with an expression of panic “Mate with? Control group? What do you mean?”
I wasn’t sure what I meant, but I pretended I had a plan.
“In lab rats, they do not select their breeding partners. I might decide that you may only have sex with women, as a control group in order to see the effect on your desire level when you play with yourself in front of me,” I said. I was completely throwing stuff against the wall to see if any of it made sense. I expected my sister to tell me to go to hell. I knew what I was saying was outrageous and I wouldn’t blame her for pushing back.
I still intended to insist she do it, but ultimately, I was prepared to relent and change my mind. I just didn’t want to seem like a push over.
“Okay,” my sister frowned as she considered the implication. “You are going to pick out some guy or girl for me to fuck at random? Is he going to know it’s an experiment, or am I supposed to pretend I like him?”
I did not expect that response – not at all. I expected her to tell me to go to hell. Even as agreeable as my sister had been up until this point, I did not expect this question. My idea was half-baked at best, and I had assumed that her sex partner would still be somebody like Ophelia that she already liked.
“You asked me for yes and no answers, Patience. You expect it to be black and white,” I complained. I was stalling while I tried to think of my answer. “You might be given an assignment to ride a dick or eat a pussy – and I would expect you not to complain and bitch. You said you wanted me to transform you into a slut, didn’t you?”
“I meant like hypnotizing me or something to make me more adventurous. I didn’t think you would make me just spread my ass and bend over for a total stranger,” Tiffy’s hands were on her head, and she was back in the position that I had put her in earlier. She wasn’t yelling or screaming – she seemed passionately worried. “Are you going to make me charge money? Is that why you asked if I gave head for cash?”
I hadn’t thought about that either.
“I would not allow you to handle the money,” I said.
“Wait a minute, I said that I would be your lab rat. I’ll ask to play with myself, if you won’t get pissed off if I come to your room all the time. I’ll do better at holding out and delaying my orgasm, and I guess I’d fuck a few guys that I don’t even know, but I didn’t think you’d do these kind of experiments.”
“What kind of experiments did you think I’d do?”
“I thought you’d probably put stuff up my butt and stick a thumb tack in my tits or something to see if it made me cry. I didn’t know you wanted me to be a whore.”
I wanted to explain that I hadn’t had any preconceived notions before Tiffy barged into my room. I wanted to admit that I also had no real plan and had been chiefly reacting to her questions. However, I didn’t think that I had to reveal either of those things just yet.
I was stuck on the idea that my sister had preconceived notions of what sort of experiments that I’d do and they involved stuffing her butt with objects and stabbing her with a thumb tack. I suppose it shouldn’t have come as a shock that before she walked into my room, she had thought about what she may be expected to do.
I would have done the same thing in my sister’s shoes.
“Bend over and grab your ankles, legs apart. Let’s see that asshole of yours before I answer your question,” I instructed firmly. I hadn’t had the audacity to spread my sister’s ass cheeks even after she came because I thought I’d really be crossing a line that was ultra-taboo and that I may be pushing her too hard.
However, after she said what she had about sticking things up her ass, I decided to find out just how seriously my sister was about her offer to be my lab rat. I don’t think she even hesitated when my sister bent over. She simply admitted as she stuck her ass out that she wasn’t limber enough to touch her toes and referenced her gut in her self-deprecating way.
“Hold your ass cheeks apart as wide as you can, then,” I insisted. My sister’s asshole was now exposed fully to me – no secrets, nothing hiding. The hole wasn’t winking at me – it was staring. It felt like the naughtiest thing I could ask to see -and something she shouldn’t be showing me.
I was fascinated with it – and the fact that my sister seemed to have no modesty as far as her asshole was concerned. The expression on her face was, “It’s just where I poop from – take a look,” as if it meant nothing to her and didn’t humiliate her.
I liked how bold she was about that.
“My experimentation will not be strictly sexual in nature, and not focused on your pleasure, or frustration,” I explained as I composed myself and took as many mental snapshots as I could of her cute, pink asshole. “I am simply establishing that you told me that you will do ANYTHING that I tell you, and what I might expect of you before I waste my time.”
“I didn’t think you’d want me to fuck total strangers,” my sister admitted.
“Wider, please,” I forced her to stretch her ass cheeks apart while I measured the circumference with the protractor. “Is it the number of sex partners that bother you; or that you may not be familiar with them in advance?”
“I am not sure,” my sister’s asshole puckered when she was uncertain – winking at me. “I think all of it. I have to get my head around it. Can you give me some idea of how many guys I might fuck in a week on average?”
I couldn’t – because I had no idea.
“You aren’t worried about how many women I may make you eat out?” I asked as I tapped on her asshole – testing how it reacted to touch and watching as the wrinkles smoothed out and the tiny hole squeezed close.
“Bring it on, If you have a bunch of women that want me to eat them out, I am down for that,” she chuckled. I think she was starting to realize that I was full of shit and that I didn’t have anyone in mind.
“I am just trying to understand if you have a concern about bi-sexuality. I would probably limit who you mate with. If you are worried about me taking you to the beach and making you whore yourself out to total strangers. That is a very unlikely scenario.”
“Okay,” she replied.
“Bend your knees a little more,” I said as I measured the distance from her asshole to her taint, the length of her ass crack. I could smell the slight scent of butt sweat and it was strangely arousing.
“Do you like my pooter? I assumed you were an ass man.”
“Why is that?” I asked as I examined it. My sister had smallish breasts, but her ass was huge – and gave her body a pear shape.
“You are always looking at my butt around the house – like maybe I forgot panties or something, and so I figured you would be into it,” she said it so plainly. I cringed when she said that because I felt like I had been discreet. I didn’t realize that my sister noticed me looking when she walked past – I especially enjoyed it when she wore tight fitting Yoga pants that showed off her ass crack through the material.
I was a bit worried that my mom knew I was looking at my sister’s butt. I doubted my dad would be that observant, but I would die if my mom thought I was a perv like that. I didn’t respond to her question.
“How often do you do anal?” I asked.
“I told you that I haven’t been fucked for months,” she reiterated.
“Yes, you did. However, I want to know how often you do anal with a partner – one time in ten?” I asked – assuming she did one or the other.
“I don’t have any limits in bed – if a guy wants to stick it in my butt, or my mouth, or my pussy, or all three – It’s usually a combination,” my sister said almost proudly. I nearly choked. I was glad she didn’t see how shocked I was by just how cavalierly my sister admitted she took it up the ass.
“We’ll be testing what can fit in your ass,” I said as I tapped on the hole again – noticing that I could barely stick a match-stick in it.
“Okay, that’s fine,” she said without concern, adding only, “If it’s like as big as your hand, you’ll use lube, right?”
As big as my hand? Wow.
“Have you ever been fisted?” I asked.
“Yeah, by Ophelia, and I’ve fisted her – but in front of my boyfriend. It’s not like we like smelling our own shitholes. I haven’t ever orgasmed through anal, but I have had guys jizz in my butt before. I don’t really see the appeal. It’s stinky and gross, and my pussy is tight.”
I was finding it hard to think straight. I wanted to take a break and jerk myself off.
“Dalton?” Tiffy sounded worried that I had stopped talking to her. Her tone made her sound vulnerable - like she was desperate for my attention and validation.
Tiffy stood there in all black, arms crossed, heels clicking against my floor. She almost never knocked on my door, but fortunately, she rarely ever talked to me – much less visited me. She’d been in her “rebellious” goth phase for as long as I could remember—not that anyone in the house cared enough to rebel against.
"That 'science thingy,' as you call it, is the Regeneron Science Talent Search," I said, leveling a look at Tiffy. "It required over 800 hours of research, a formal research paper, and surviving multiple rounds of scrutiny by PhD-level scientists. I had to meet strict pre-requisites, including original, independent research at a near-college level."
I folded my arms. "It culminated in a full-scale project presentation judged against some of the brightest high school minds in the country—future physicists, medical researchers, AI pioneers. And it earned me a finalist spot, which, by the way, comes with scholarships and a shot at meeting Nobel Prize winners.”
“Whatever,” she stood there as if waiting for me to say something else – or trying to make up her mind about something. She was wearing a skimpy outfit; despite being heavy-set. My sister has a pretty face, but she’s quite sensitive about her weight. She pretends it doesn’t bother her, but if you even imply that she’s fat, she can be quite vengeful.
“What do you want, Tiffy?” I sighed as I closed my dog-eared copy of Solaris by Stanisław Lem. It was one of my favorite science fiction books. It’s about a psychologist named Kris Kelvin that is sent to a space station orbiting the mysterious planet Solaris. When he arrives, he discovers a sentient planet that is incomprehensible; it’s an intelligence so alien it either refuses to communicate or simply doesn’t see the point.
My sister would identify with Solaris. She didn’t do small talk, didn’t explain herself, and didn’t care if anyone understood her. She existed in her own world, reacting on some logic the rest of us weren’t privy to. And that made me Kris Kelvin—stuck in close proximity, trying not to set off something I barely understood.
“Do I have to want something to come and tell you that I am proud of you?” Tiffy replied coyly. I didn’t buy her nice act for a second. “Did your Regeneron thingy come with any prize money?”
“Even if it did, I’d give it to Mom and Dad, and not you,” I crossed my arms, and sat cross legged on my bed – my body language made it clear that I wasn’t interested in conversing with her.
“Don’t get your undies all in a bunch, Dalton. I am not asking you for money. I just wanted to find out what science project you would work on next. If you win money, you could hire a person to help you test out your theories or whatever.”
“I didn’t win any money, and I don’t need a human lab rat,” I scoffed at the very idea of doing human trials on a person.
I didn’t expect my sister’s expression to brighten, but it did. Tiffy had a lovely smile – the kind that could brighten any room. It was unfortunate she almost never allowed anyone to see it. The times I remember seeing her smile were when I fell off my bike and skinned my knee or when my mom accidentally dropped my birthday cake on the floor. I recall she smiled toward the end of the Titanic when the mom locks the door after realizing she can’t escape before the boat sinks.
“Why does that amuse you?” I asked.
“I like the term human lab rat; that’s kind of cool. I was going to ask if I could be your specimen or whatever, and help you test out your theories. I am not book smart like you, so I probably couldn’t be a lab helper, but I could volunteer to do tests and stuff.”
I was taken aback by my sister’s strange request. She never did anything for me. She never lifted a finger around the house to help my mother clean or do chores. She barely did her own homework, and my guess was this was some sort of elaborate trap.
"Why would you do that?" I asked.
"I don't know," Tiffy said with a shrug, her tone flat. She was lying. My sister never did anything without a reason. It was like her to be aloof and detached. “I was hoping to earn some money,” she corrected when she realized that I was not buying it.
“Well, I didn’t earn any money,” I shrugged dismissively as I picked up my book and re-opened it. I was hoping that would be a polite signal that she should leave my room. My room was my domain – the place I spent most of my time. it was a treasure trove of my favorite things - computers, video games, television, books, action figures, test tubes, electronic kits, all the nerdy stuff that I had. I loved being alone and solitary, and in that sense – my sister and I were alike.
“If I agreed to become your lab rat, would you stand a chance of earning money on your next science experiment?” she asked – clearly fishing for an opportunity but still trying to sound ambivalent.
“You don’t even know what I am going to research next, why would you offer to be a test subject?” I was puzzled, but I didn’t wait for a response before changing my question. “Why would you want to hang out with me? You don’t like me.”
My sister seemed uncertain of how to respond to that. She could have said something about us both growing up and moving away with a chance of starting new lives and seldom seeing each other. She could have said we live in the same house but seldom leave our rooms and how we should get to know one another.
“That’s fair,” she shrugged. “I can come across like a bit of a bitch.”
“Come across LIKE one?” I laughed at the thought. “You aren’t LIKE a bitch. You ARE a bitch if there ever was one. You stormed into my room as if you owned it and then called me a scrotum while minimizing my accomplishments.”
“Sorry,” she seemed contrite, unsure of herself, and that was odd. I had never seen my sister be vulnerable before. “Well, what are you going to research? I would like to help if I can.”
“I really don’t know,” I answered truthfully. “I poured so much time into my last project that I haven’t thought about it. The field of science is vast, and I have interest in everything from physics, genetics, AI, and chemistry to medicine. The first step for me would be to do random experiments and see what inspires me. I doubt any of that would interest you.”
“Do you think you could make me thinner?” she asked – it wasn’t sarcasm, and it came across as an authentic request for help. I could have been snarky, but I felt like she may be genuinely looking for help or a shortcut to better health.
“A good diet, willpower, exercise, and some nutritional supplements could do that. If you want me to put something together for you, I will,” I offered.
“I’ve tried diets, and I hate exercise. Do you think maybe you could give me a pill or a shot that would make me thinner and hotter?”
I was no psychologist like Kris Kelvin, but it didn’t take a degree in psychology to recognize that my sister had low self-esteem and a poor self-image and wanted some magical panacea that would make her a different person – or at least outwardly so. I hadn’t really thought about it before, but part of why she could be such an insufferable asshole and lashed out at people was probably insecurity.
“Science doesn’t work like that, Tiffy. I can’t experiment on a person and just make them lose weight. It would take years to develop something, and it would never start with human trials. It could cause harm or have unexpected side effects.”
“I don’t care about that, and I’d sign whatever waiver you want – maybe you could make me taller, prettier, or smarter. It doesn’t have to be thinner.”
I shook my head. I could have said she was pretty and intelligent. I felt like she might be fishing for compliments. I’ve seen what happens when my parents tell her she’s pretty. She scowls and doubles down on self-deprecation. I also knew that she read a lot of Goth books and was intelligent when it came to subjects that interested her.
“Look, give me pumpkin-sized titties, and I’ll do whatever you want,” she insisted stubbornly, shifting her weight to her hip and folding her arms.
I chuckled. “I can’t do surgical boob jobs, and that would require me to not only see your tits but to actually touch them. I am your brother!”
“That’s why I trust you,” my sister popped her top open quickly to reveal her milky white tits. They were fat and chubby and hung down, but still remarkable to me. “There -you saw them. So, we have that out of the way. I am not asking you to do surgery unless you think that’s the only way. Give me a pill or something and make them look natural but not so saggy and ugly.”
“The sag is hot, and you’ve got some huge strawberry nipples,” I blurted out without thinking about how that sounded. I stopped myself, but it was too late, and I blushed. I loved porn almost as much as I loved science, and even my sister’s natural tits were a welcome sight – despite the guilt I felt about staring at them.
“It’s science, so it wouldn’t be sexual, but you can grab them, touch them, squeeze them, whatever. I’d be your lab rat. As long as we can keep it between us, whatever happens in your room is just science.”
I arched an eyebrow. I would have been surprised that my sister wanted to have a discussion of any length with me. I was absolutely floored that not only did she want to talk to me, but she offered to help me with my science projects. I could hardly accept that she took her tits out in front of me like it wasn’t a big deal and continued to stand in front of me like that.
I assumed all of this was some bizarre attempt to trick or demean me – or use me to her own ends. It just seemed a bit too strange to be true. The concept of Occam’s razor “The simplest answer is probably the truth” doesn’t work on my sister because she often defies my understanding of logical thinking.
I could have just shot her down and been done with it and that would have been the safest thing to do. However, I was curious about her motivations and bored enough to continue the discussion as long as it remained hypothetical. If I am being honest, I wanted to keep looking at my sister’s tits, but despite that I looked away from them when I asked my next question.
"What if I’m not interested in altering the composition of your body? What if I’d rather explore other types of science? For instance," I leaned back, tapping my chin, "a sensory deprivation study. I could test how long you last in complete darkness and silence before your brain starts hallucinating."
Tiffy narrowed her eyes. "You want to lock me in a closet and see if I start talking to ghosts? I would have always been down to do that."
I realized that I hadn’t quite made my point. My sister did love darkness, and I assumed she was being a bit facetious. I glanced at her boobs, making mental snapshots because I assumed she’d leave after I asked my next question.
“As I told you earlier, I have many areas of interest, and I’d probably want to perform a wide range of exploratory experiments before settling on one project. You seem focused on helping me because I might be able to help you alter something about you. What if I’d rather explore other types of science? For instance," I said, flipping through my notes, "a study on nerve response and pain tolerance. We could see how different temperatures affect pain perception. Ice baths, heat exposure, maybe even a mild electrical impulse—"
“Would you eventually get around to making me learn to get off from pain or something?”
Tiffy seemed receptive, almost excited by the proposal. I assumed she just didn’t understand the repercussions of what I was telling her.
“No, If you were truly my lab rat, your happiness would not be my concern unless I were trying to measure the relative manner in which you process pleasure. Which I suppose I could do, but we are brother and sister – and I am not talking about tapping your knee to test your reflex in that hypothetical. I might be testing how sudden blasts of cold air affect your nerve response. You'll sit here while I direct a controlled burst from my modified air compressor at you – and then measure whether or not the cold air could make your nipples hard -or even the sight of the compressor.”
“Cool, sure,” she shrugged.
“It wouldn’t result in weight loss, increased intelligence or height, or even bigger boobs – at best, it could be mild stimulation for you, and at worst, it could cause frost burn. Would you really agree to that if it didn’t benefit you directly?”
“Why are you trying to talk me out of helping you? If the tables were turned, and you came to me and told me you’d do whatever I want, I’d use you as a human ashtray and flick my butts into your mouth while I sat my fat ass on your back and used you as a human chair,” my sister painted a devious mental image for me.
The degrading position she’d put me in sounded like classic Tiffy. She’d always been a bit of a bully to me when we were little – calling me pencil dick and nerd.
“I wouldn’t come to you and volunteer for that; are you going to allow me to set up an experiment where I use you like a lab chair?” I joked.
“I told you that I am down for anything, and I’ll be your lab rat.” If that’s part of the experiment, then I am there for it, Dalton.”
I didn’t expect her to sound so sincere or to answer my question. I assumed she knew that I was joking. I was taken aback and remained silent as I tapped my pen.
“Fine, I’ll go find some other way to kill time,” my sister started to button her top and leave.
“I was thinking, Tiffy.” I held up my hand. “It’s not every day that we talk, and I didn’t expect this or ask you to show me your boobs. Are you really willing to do ANYTHING I say and allow ANY experiment? Have you given any thought to the repercussions of that? What if I chose to use it as a human Petri dish and incubated the flu to study its effects on you? Or did I decide to chop you up into little bits?”
I assumed that my sister would surely see the folly of her request, and so I glanced up fully at her boobs so that I could take one last long look before she left in a huff.
“The fact that you are concerned enough about me to worry about stuff like that tells me that you aren’t a mad scientist and a psychopath, Dalton. Anyway, If you were to do something like cut off my tongue and sew it to my asshole so that I have to lick my shit when it comes and taste it – don’t you think you would get in trouble? So, do I really need to spell things out like that?”
“I have a hard time understanding why you are willing to write a blank check with no parameters or boundaries defined without a promise that I can play the Wizard of Oz and give you a brain and boobs like the Goth version of Dorothy,” I replied.
My sister found that amusing, and she snickered – lighting up the room again and acknowledging my point. “The fact that you didn’t just tell me whatever I wanted to hear in order to get me to be your Lab rat means that I can trust you -I know there are no guarantees that whatever your research would benefit me.”
That was pragmatic and a compliment. I acknowledged and thanked her while I gave it some thought. “What prompted you to come here today? Was there something that happened?”
Tiffy made a derisive ‘pshaw’ noise with her mouth when I asked the question and told me that I was the smartest person that she knew. “I’ll never be that smart, but maybe I can contribute to your research, and why are you making me beg?”
“I am not asking you to beg. If you want to be my lab assistant, then you would have to be interviewed. I think understanding your motivation for the job would be a reasonable thing to ask,” I countered.
My sister didn’t like it when I said lab assistant. “Who said anything about assisting you? you can test stuff on me, but I am not going to organize your books and dust your shelves or something.”
“You said you’d do anything I say, and then you said there would be no boundaries or limitations, and now you are telling me what you won’t do,” I found that to be classic Tiffy – a contradictory offer.
“For a smart guy, you really are dumb,” she frowned. “Okay, I’d be your lab assistant as well, but if you want to know my limits, then I get Friday and Saturday nights off,” she said firmly – like it was not negotiable.
Now we were getting somewhere – I could entertain a reasonable offer of assistance. The open-ended one sounded too unrealistic, and somewhere along the way, she’d get pissed off and quit when I pushed the wrong button or framed things the wrong way.
“What time does that begin?” I asked for clarity on her working hours.
“Night,” she insisted in a patronizing way. “You know? When the sun goes down and it gets dark out? I am a creature of the night – so I can do whatever I want from sundown to sunrise on Friday and Saturday – any other time I do what you tell me.”
I arched an eyebrow – intrigued. “Any other boundaries?”
“I am not going to stop smoking cigarettes or cloves, drinking, or doing drugs,” she said firmly.
“What if I require it of you for an experiment?” I fired back. I didn’t approve of any of those things, and I knew our parents didn’t either. I presumed that my sister didn’t shoot up heroin or do hard drugs of any kind, but it wouldn’t have surprised me if she frequently smoked marijuana.
“You asked for my limits, and now you are telling me that I can’t have any limits?” my sister tried to turn my logic back on me and make it sound like I had made two mutually exclusive statements.
“I may decide to limit or completely stop any of those activities, as I will be providing you with a special diet and exercise regimen to reduce your weight,” I instinctively replied. I didn’t give that particular offer much thought. I happily performed a Google search for my sister to help her before we started talking about being my lab assistant/test specimen.
I was surprised that she stopped slouching and smiled at me broadly – quite pleased. “That would be cool! So, you are saying I got the job?”
“Do you have any other limitations or boundaries as a test subject or assistant?”
“Don’t transform me into a normie has-been or an insufferable Bimbo Barbie doll,” she replied without hesitation.
I liked the word “transform,” and I kind of keyed in on that – it inspired some wheels to start turning in my head. I had some idea of a Barbie Doll – a blonde, vapid, narcissistic bimbo that thinks only of themselves and shallow thoughts. I asked her what a normie has-been was.
“Normal,” she shrugged. “Don’t try to turn me into Tina Turd the Nerd,” she explained. “I don’t want to be a science geek and stop dying my hair blonde or look boring and act boring. That’s why I don’t want to be your assistant. I don’t want to measure beakers and talk about “The Structure of Scientific Revolutions,” she pointed to a prominent book title on one of my shelves. “I am not going to study science and be turned into a super brain.”
“Didn’t you tell me you want to be intelligent?” I asked. I had no intention of turning my sister into anything she didn’t want to be, and I had no delusion that I had the capability to transform her into anything – much less a super brain. However, her request puzzled me. If she truly thought I could enlighten her – why wouldn’t she want that gift of superior intellect?
“I don’t mind if you experiment on me with hypnosis or mind control or something, but I don’t want to be turned into someone boring. If you are going to make me into something, turn me into a super slut, or someone interesting. I can be boring on my own.”
Wow, that was quite a revelation. Arching an eyebrow, I could hardly express how intrigued I was by what she said.
“You’ll allow me to alter your self-perception and implant suggestive behaviors as long as those behaviors meet your approval, is that it? I can’t make you a better student, or do you want to do chores around the house? Create a Tiffy 2.0?”
I have to admit that while I doubted I had the ability to implant suggestions, I enjoyed the hypothetical prospect that I could improve my sister.
“Tiffy 2.0 sounds awesome,” she concluded. “I don’t really want to be a maid or a better student, but I am not going to say no. Can I ask that if you hypnotize me, it’s where I don’t actually remember it while I am under? Chores are fucking death!” she frowned dramatically over how boring and tedious that was.
“As my Lab assistant, I would require you to clean my room, sort and organize daily except on Friday and Saturday night, whether I can successfully hypnotize you or not, are you sure you would want that job? Alphabetize my books, bring my laundry to the bin, fold it, and help me set up and record experiments?”
My sister gave it only a moment of thought before shrugging. She didn’t seem enthusiastic. “I will do whatever you tell me, but I am probably going to complain about it,” she promised.
“What if I forbid you from complaining and insist that you address me with respect?” I asked. I was unconvinced that my sister would stick with her offer after the first time that I asked her to do something she found boring.
“You’d have to make respect you,” she replied – staring me right in the eyes. My eyes flicked up from her bare nipples and locked with hers. I could tell that she was waiting for me to ask her how to make her respect her, and I didn’t take the bait.
“You aren’t providing much incentive for me to want to offer you the job. If this were an interview and you promised a leading researcher that you were going to be a curmudgeon that complains, do you think you’d get the job?”
“As a lab rat? Why is it so important what I think of you, anyway?” she asked. “Do lab rats have to be nice to the Researcher?”
She had a point. “Researchers use a combination of positive and negative rewards to get the behavior they desire from their lab rats. I may decide to grant you a special dessert if you have performed adequately that day, or I might require you to stand in the corner of my room when you first enter if you are a bitch, until your behavior improved.”
My sister barely reacted. I expected her to cringe or refuse, but instead, she nodded in agreement that would be acceptable. I expected her usual sarcasm, but instead, she just looked at me, waiting.
I tapped my pen against my notebook. "Alright. First, baseline data collection."
She nodded. "Tell me what to do."
“Remove all of your clothing, everything – shoes, hair clips, earrings – all of it.”
My sister began to undress right in front of me – no modesty, no shame. She went for it. I wondered if she had expected it. I would have expected some reluctance. I picked up my notebook and began to journal her behavior in my lab shorthand – so that in case she read it, she would not fully understand what I wrote.
“Don’t tell Mom and Dad that I am your lab rat,” my sister said as she rolled her panties down her thighs – revealing her fat, hairy pussy.
“I would tell them you are my lab assistant – helping me with my research if they need to know. I won’t keep secrets from them, but I won’t advertise it either. It’s possible they will want to enter my room during our research.”
“Do they ever come into your room now?” my sister stopped undressing for a second and gave me a knowing look. “They don’t come into my room either. Lab assistant is fine but tell them you are paying me. They won’t believe I am doing this for free,” she advised.
“I am the one who gives instructions,” I replied and added that I wanted her to remove her chewing gum. My sister didn’t think that I had noticed her quietly chewing the gum. She took it out and handed it to me – it was still wet with her saliva. I put it in a napkin, but I was tempted to put it on her nose like an angry schoolteacher.
“Stand up straight, shoulder’s back. Hands above your head, palms flat on the top of your head, legs apart, I want to measure you,” I removed a ruler and protractor from my desk. The metal protractor looked intimidating and had a sharp point.
[[[ image 01_titty.jpg goes here centered ]]]
My sister complied as I studiously measured her from every angle. I didn’t just measure height. I measured the distance of her ankles to her toes and the length of her collarbone and neck. I tried to pretend that seeing her naked didn’t affect me, but it did. I could smell her body – the sweat, the faint scent of her pussy and I noticed tiny things like how her skin reacted with goose bumps to the slightest touch.
My initial measurements were very innocent but quite thorough.
“Are you going to measure the circumference of my nipples with that pointy thing?” Tiffy asked as she nodded at the stainless-steel protractor that I had left on the desk in front of her while I used the ruler.
“Yes, I am getting to the more intimate parts of your body,” I tried not to stammer nervously. I measured the tip of her nipple to the base- avoiding touching it directly. I liked how stubby and fat it was. “I am going to have to think of a specimen name for you. Tiffy is too personal; when you are Tiffy, you are allowed modesty. As a specimen, you do not have privacy, and I will need to be free to touch you anywhere.”
“What’s my name?” my sister didn’t argue or balk – she accepted it. When I gently touched her nipple, I expected a slap, but it didn’t come. I used the protractor to carefully measure the distance around her nipples and found that they were each slightly different. I also measured how one was longer than the other.
I didn’t answer right away because I hadn’t thought about it. I wanted it to be something ominous or cool. I was trying not to let on that I was flummoxed by my sister’s nudity – it was so distracting, and I had to stand behind her while I adjusted the erection in my pants.
“Your name is Gothopotamus,” I quipped, testing to see what she’d say to that. I stood behind her and watched her clench her ass cheeks angrily. I don’t know why it amused me to see her frustrated and not say anything to me – but it did.
“No, that’s quite right, it’s too long. Specimen XXL – or 2XL?” I scratched my chin as I squatted down, eye level with her hairy pussy. “What do you think of that?”
“Do you have to tease me about how chubby I am?” she asked – pouting and vulnerable.
“I’ve seen how you react to our parents praising you and saying you are pretty – you tend to yell at them and dismiss it,” I explained.
“I know I am not a beauty, and I don’t want to be patronized. That would be like me calling you muscular, Dalton,” she explained. My sister was pretty – and I assumed she knew it. It seemed illogical for her to refuse to accept it as far as I was concerned.
I decided to take bold action, and I placed my hand between her thighs – and stared up at her. I waited for my sister to look down her nose at me and tell me that I was going too far. She had to know my next move was to touch her pussy. I waited for the scolding that never came.
“What are you measuring down there? the circumference of my fat asshole? Or the shadow that my slit makes on the carpet?” she chuckled. It was so crass and vulgar – that I nearly shot a load in my pants.
“Patience,” I insisted that my sister stop rushing me. I was trying to get the courage to go a little further with my examination, and I didn’t want to tell her that – so I acted like it was intentional that I was making her wait.
“is that my Specimen name?” she asked – a trace of excitement in her voice. I wondered if she thought I was being audacious.
“Yes, because you lack it, and by the end of your term as my lab rat, you’ll have had to develop it,” I declared. It wasn’t the ideal name because it was longer than Tiffy – but I liked it.
“At least it’s not Tina. You can call me anything you want except that,” She decided.
“I will make a note of it on your list of do’s and don’ts as my specimen, but my question is, will you answer to it, Patience?” I asked as I slid my finger up to her pussy – delicately and ever so slightly parting her pussy lips so that I could try to measure the gap with my ruler.
“Yes,” she swallowed quietly. I liked where this was going, and much to my chagrin, I felt moisture on my sister’s pussy lips. I had never touched a woman’s pussy, and while I knew that girls got wet – I wasn’t sure what to expect.
“Sorry about that,” Tiffy politely apologized – clearly aware of what I was doing and how she was physically reacting to my touch.
“It’s perfectly natural, Patience. Your body is simply reacting to physical stimuli. The autonomic nervous system doesn’t distinguish between intentional sexual contact and other forms of sensory input—it only processes pressure, temperature, and nerve activation. Tactile stimulation, particularly in areas with a high concentration of mechanoreceptors, can trigger increased blood flow due to vasodilation. The parasympathetic nervous system mediates this response, preparing the body for potential activity, even when the stimulus lacks sexual intent.”
I touched her even more lightly, measuring taint – distance from asshole to pussy without actually spreading my sister’s tightly clenched butt cheeks. I wanted to see that part of her, but I was a bit too timid to dare that until I finished measuring her pussy.
“Additionally, the skin contains Pacinian and Meissner corpuscles—nerve endings that respond to deep and light touch, respectively. Depending on location and sensitivity, their activation can send afferent signals to the brain, which may be misinterpreted as arousal. This is why certain medical exams, massages, or even accidental pressure can elicit similar responses. It’s an entirely physiological reaction, independent of conscious desire,” I said as I carefully measured her – careful not to pull her labia, touch her clit, or clitoral hood.
“Please tell me this is not the first pussy that you’ve ever touched, Dalton?” my sister sounded incredibly disappointed to the point of frustration.
“No, of course not,” I lied. I’d never come close to going this far with a girl. I wouldn’t have known the first thing to say to one in order to coerce her to let me kiss her – much less get this far.
“Whose twat have you played with?” she asked.
“I am not playing with it, Patience!”
“Trust me, I know – you are acting like its liver on your plate and you are grossed out by it. It’s humiliating – do I stink or something?” she asked – scrunching her nose and looking mortified.
“I was trying not to overly stimulate you,” I assured her, blushing myself.
“Mission accomplished,” she assured me that I was far from doing that – I noticed that her pussy was bone dry and no longer juicing up. I felt angry, exposed, and vulnerable -like I should lash out at her for exposing me as a fraud. I knew that I had no business touching my sister’s pussy. I was suddenly recognizing so many conflicting emotions – guilt that I had touched my sister, anger that she knew I was lying about my experience, frustration that I had no clue about women’s bodies.
“I am sorry that I am not masturbating you to orgasm, Patience! If you came here to get your rocks off, then you came to the wrong place. You asked to be my lab rat – the first step is to baseline you. I have no interest in finger fucking you – but once we pass the threshold where I insert a finger – there is no going back to normal.”
“I think we passed normally a long time ago, Dalton. I am sorry for being a bitch. I will hush and let you take a good, long look under my hood. I just haven’t had any dick for a while – and I am a little horny, and this is doing the opposite to me,” she grunted.
“How sexually active are you?” I asked as I adjusted my posture and measured the distance of my sister’s clitoral hood.
“Depends on what day it is,” she giggled before becoming serious. “A lot of girls and some guys think I am easy and fuck a lot, but the truth is that I am a fatty and don’t get as much action as people think. I dress a little slutty, but I haven’t had a regular boyfriend in months. I guess the last time I had actual sex was back then.”
Holy shit, I was rocked by my sister’s honesty. I couldn’t imagine a scenario in which my sister didn’t snarkily dismiss me if I had asked her who she was having sex with. My parents had never met any of her boyfriends- my sister always acted aloof and like she was a free agent who fucked anyone she fancied.
“I have a couple of girlfriends at school, I ate out Ophelia a few months ago when we were bored, but she didn’t reciprocate – so when you were whisper-touching my pussy like it was going to bite you and swallow you whole, I thought maybe I had genital warts or something weird. I don’t have genital warts, do I?”
I wouldn’t have been able to tell her even if I knew what they looked like. “I’d have to run blood tests,” I bluffed. I knew Ophelia – she was a hot brunette, very tall, and always looked aloof like she was angry at her dad. The thing that I noticed about Ophelia was that she seldom wore a bra to school, and she had saggy boobs that hung down in her tank top. Her nipples pointed down, and I often wondered why she didn’t wear a bra – assumed that she might not want to draw attention to them by not wearing a bra.
“What about oral sex?” I asked – still measuring.
“On you?” she scoffed.
“No, on whoever – do you give blowjobs to random guys at school or anything like that? charge money?”
“You think I am a whore?” my sister sounded incredulous. She was standing with her legs apart, naked, and allowing me to play with her pussy. I didn’t think the question was that far-fetched.
“As my lab specimen, you must answer all questions truthfully and fully, or else I will potentially collect invalid information. You seemed to want money when you first approached me about this job. If you are willing to do this – it wouldn’t be out of the question that you’d give head for money.”
“True,” my sister admitted and added that she didn’t do that. “Guys don’t just randomly walk up and whip out a hundred-dollar bill and ask for girls to go down on them.”
“I know that,” I said. “You hang out with some odd characters,” I referenced the goth kids at school who dyed their hair and pretended to be vampires while smoking behind the cafeteria. “It may be some kind of free-love/free-sex kind of thing.”
“Yeah, I am a free-use slut – I fuck anyone, anytime, anywhere,” she said with all sincerity.
“Really?” I asked – quite surprised. That sounded strangely enticing.
“No, but I am about to run out in the street and fuck the first guy walking down the street; can you please stop tugging my clit? You are teasing the fuck out of me, and getting me all fluster-fucking horny, Dalton,” she breathed in and out. I didn’t realize that my sister’s pussy had begun dripping again or that I had been non-stop tugging her clit for no apparent reason while I asked the questions – I must have become distracted by my own arousal.
“You’ll be regularly soaked, and I am going to tease you to the edge of orgasm. Are you already complaining?” I kept performing the same move. I was embarrassed that I had no real scientific reason for why I had done that and shocked that my sister let me get away with it for as long as she had.
“I told you that I would do what you told me, and I might complain, Dalton,” my sister started to pant, a panicked look on her face. “Are you sure…are you sure….are you sure...you want to make me….oh, oh, oh, please don’t, please, stop, it’s embarrassing, Dalton – Can I..” she brought one hand down to her pussy, to force my fingers away from her clit and masturbate herself to completion.
“No, you may not, Patience,” I slapped my older sister’s hand away and talked down to her like she was a petulant, naughty child. I kept frigging her – up and down, up and down.
“At least put a finger in me and press down on my clit; this is torture, Dalton, I wouldn’t jerk you off and keep you from cumming – I can’t take it.”
“You can take it, you will take it, and you aren’t allowed to cum without permission while you are my specimen,” I insisted and kept right on lifting her clit flap up and down. My sister started to wiggle and hop from foot to foot like she had ants on her legs and couldn’t slap them off.
“I can’t cum EVER without permission? Or just right now, like this?” she gasped in horror. She had returned the hand I slapped to the top of her head but removed the other and brought it to her breasts.
“Naughty Patience, keep your eyes straight ahead, shoulders back, and both palms flat on top of your fat head,” I frowned. I didn’t mean to call her fat – but I liked that my sister didn’t question my authority. She did as instructed.
I had never intended to forbid my sister from masturbating herself or having an orgasm. I simply meant that she could not cum right at that moment. I honestly had no idea what she would physically do when she came. My experience was limited to watching adult actresses’ fake orgasms on porn clips.
“Please, Dalton? You can’t be that cruel,” my sister couldn’t stop gyrating her hips, and her tummy quivered. She placed her other hand on top of my head and grabbed a bit of my brown hair.
“Hands off of my hair, slut!” I insisted. My sister had told me that I could call her anything except for Tina – I just tested that theory, and she didn’t slap me or tell me that was too far. I slapped her hand away from my head.
“Please, may I cum, Dalton? I am so close; I am ready to cum like this; just push down on my clit as if you hate me – I am sorry I can’t hold this position, I’ve never..oh…never…never..oh.”
I felt like my sister was giving me the joystick cheat codes on how to get her off – and it was working!
I was going to ask my sister if she really wanted to be my test subject after all. I had already asked her that question, but I felt like consent was key, and now that we had begun – maybe she was having second thoughts. However, her eyes rolled into the back of her head, and her toes curled up. Tiffy’s tongue fell out of her mouth, and she began to drip so much cream from her pussy that it was coming out like spit.
“Punish me if you want, but I can’t take it, fuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuck,” my sister grabbed my head and nearly pushed my face to her pussy to lick it, while fucking the air. She squatted and then laid down flat on my carpet while writhing and finger fucking herself. She rolled over on her stomach, and humped her finger, like she was fucking a man. I saw her tight ass cheeks flap open a few times, and her cute- round pink asshole. It was just for a split second.
I felt like my sister was showing me something that I wasn’t supposed to see – and now my cock hurt as it shifted uncomfortably in my pants. I was turned on but obviously not quite as much as my sister.
It took her a minute and forty-three seconds to achieve orgasm and then compose herself. I know because I measured it and imagined a diagram that I might create of the velocity and intensity of the orgasm relative to how completely uninhibited my sister became.
When she was finished, she looked up at me like she couldn’t believe what she had just done. “I am sorry about that, Dalton; I couldn’t hold out any longer. Did I pass the test?” she asked.
I had no idea what test she meant.
“It wasn’t a test; it was a baseline to see how long you could last,” I interpreted my sister’s question and added “There was no optimal score that you had to achieve.”
“It’s hard to understand you sometimes,” my sister admitted as she got to her knees and stood up. “It’s a simple yes or no, Dalton. Did I fuck up and get your finger all sticky and freak you out, or are we cool to keep doing this?”
It was hard to keep a flat expression on my face. I didn’t want to seem too eager, but my sister could probably see that I was struggling not to smile. “Yes, you did fine. I will expect you to hold out longer next time.”
“It’s going to suck not being able to cum anytime I want. On Friday and Saturday, I am probably going to fuck the banister on the stairs and go full freak-mode with my clit just because I can’t get any satisfaction whenever I want. I’ve never had anyone tell me that I can’t have an orgasm before – it sucked.”
I wanted to ask my sister if she still wanted to do this, but I didn’t get the chance. She had another question before I could respond.
“How does this work at school and stuff? I can still date, and have an orgasm with other people? I just can’t masturbate anymore?”
My sister had made these rules simply by asking me the questions – I had never dreamed she’d give me that sort of authority, or that she’d deserve that kind of structure. I hardly had any scientific rational for orgasm denial.
“I don’t know yet; I’m still in scientific exploratory mode,” I tried to be non-committal so that I could have some time to think about it. I expected that my sister would be rational and understand that we’d only just started this change in our relationship, and I needed time to ponder the ramifications of any new rule like that.
My sister isn’t rational.
She looked absolutely terrified when I failed to immediately give her a yes or no, so I decided to give her one.
“No, you may not date, and that includes casual sex for money or otherwise,” I decided to throw in a stipulation about my sister being a prostitute just to make it sound official. “I am not going to play with your twat to get you off anytime you want. If you want to have an orgasm outside of your examination time, you’ll ask permission and then I’ll tell you if you may have privacy.”
I waited for her to argue with me about that and when she stood there aghast, I continued.
“When and if I decide that you may date, I will revise the rules about sexual relief, and I may introduce a control group for you to mate with. However, I will first determine that you are on birth control.”
“I am already on birth control now,” my sister said before repeating some of my words with an expression of panic “Mate with? Control group? What do you mean?”
I wasn’t sure what I meant, but I pretended I had a plan.
“In lab rats, they do not select their breeding partners. I might decide that you may only have sex with women, as a control group in order to see the effect on your desire level when you play with yourself in front of me,” I said. I was completely throwing stuff against the wall to see if any of it made sense. I expected my sister to tell me to go to hell. I knew what I was saying was outrageous and I wouldn’t blame her for pushing back.
I still intended to insist she do it, but ultimately, I was prepared to relent and change my mind. I just didn’t want to seem like a push over.
“Okay,” my sister frowned as she considered the implication. “You are going to pick out some guy or girl for me to fuck at random? Is he going to know it’s an experiment, or am I supposed to pretend I like him?”
I did not expect that response – not at all. I expected her to tell me to go to hell. Even as agreeable as my sister had been up until this point, I did not expect this question. My idea was half-baked at best, and I had assumed that her sex partner would still be somebody like Ophelia that she already liked.
“You asked me for yes and no answers, Patience. You expect it to be black and white,” I complained. I was stalling while I tried to think of my answer. “You might be given an assignment to ride a dick or eat a pussy – and I would expect you not to complain and bitch. You said you wanted me to transform you into a slut, didn’t you?”
“I meant like hypnotizing me or something to make me more adventurous. I didn’t think you would make me just spread my ass and bend over for a total stranger,” Tiffy’s hands were on her head, and she was back in the position that I had put her in earlier. She wasn’t yelling or screaming – she seemed passionately worried. “Are you going to make me charge money? Is that why you asked if I gave head for cash?”
I hadn’t thought about that either.
“I would not allow you to handle the money,” I said.
“Wait a minute, I said that I would be your lab rat. I’ll ask to play with myself, if you won’t get pissed off if I come to your room all the time. I’ll do better at holding out and delaying my orgasm, and I guess I’d fuck a few guys that I don’t even know, but I didn’t think you’d do these kind of experiments.”
“What kind of experiments did you think I’d do?”
“I thought you’d probably put stuff up my butt and stick a thumb tack in my tits or something to see if it made me cry. I didn’t know you wanted me to be a whore.”
I wanted to explain that I hadn’t had any preconceived notions before Tiffy barged into my room. I wanted to admit that I also had no real plan and had been chiefly reacting to her questions. However, I didn’t think that I had to reveal either of those things just yet.
I was stuck on the idea that my sister had preconceived notions of what sort of experiments that I’d do and they involved stuffing her butt with objects and stabbing her with a thumb tack. I suppose it shouldn’t have come as a shock that before she walked into my room, she had thought about what she may be expected to do.
I would have done the same thing in my sister’s shoes.
“Bend over and grab your ankles, legs apart. Let’s see that asshole of yours before I answer your question,” I instructed firmly. I hadn’t had the audacity to spread my sister’s ass cheeks even after she came because I thought I’d really be crossing a line that was ultra-taboo and that I may be pushing her too hard.
However, after she said what she had about sticking things up her ass, I decided to find out just how seriously my sister was about her offer to be my lab rat. I don’t think she even hesitated when my sister bent over. She simply admitted as she stuck her ass out that she wasn’t limber enough to touch her toes and referenced her gut in her self-deprecating way.
“Hold your ass cheeks apart as wide as you can, then,” I insisted. My sister’s asshole was now exposed fully to me – no secrets, nothing hiding. The hole wasn’t winking at me – it was staring. It felt like the naughtiest thing I could ask to see -and something she shouldn’t be showing me.
I was fascinated with it – and the fact that my sister seemed to have no modesty as far as her asshole was concerned. The expression on her face was, “It’s just where I poop from – take a look,” as if it meant nothing to her and didn’t humiliate her.
I liked how bold she was about that.
“My experimentation will not be strictly sexual in nature, and not focused on your pleasure, or frustration,” I explained as I composed myself and took as many mental snapshots as I could of her cute, pink asshole. “I am simply establishing that you told me that you will do ANYTHING that I tell you, and what I might expect of you before I waste my time.”
“I didn’t think you’d want me to fuck total strangers,” my sister admitted.
“Wider, please,” I forced her to stretch her ass cheeks apart while I measured the circumference with the protractor. “Is it the number of sex partners that bother you; or that you may not be familiar with them in advance?”
“I am not sure,” my sister’s asshole puckered when she was uncertain – winking at me. “I think all of it. I have to get my head around it. Can you give me some idea of how many guys I might fuck in a week on average?”
I couldn’t – because I had no idea.
“You aren’t worried about how many women I may make you eat out?” I asked as I tapped on her asshole – testing how it reacted to touch and watching as the wrinkles smoothed out and the tiny hole squeezed close.
“Bring it on, If you have a bunch of women that want me to eat them out, I am down for that,” she chuckled. I think she was starting to realize that I was full of shit and that I didn’t have anyone in mind.
“I am just trying to understand if you have a concern about bi-sexuality. I would probably limit who you mate with. If you are worried about me taking you to the beach and making you whore yourself out to total strangers. That is a very unlikely scenario.”
“Okay,” she replied.
“Bend your knees a little more,” I said as I measured the distance from her asshole to her taint, the length of her ass crack. I could smell the slight scent of butt sweat and it was strangely arousing.
“Do you like my pooter? I assumed you were an ass man.”
“Why is that?” I asked as I examined it. My sister had smallish breasts, but her ass was huge – and gave her body a pear shape.
“You are always looking at my butt around the house – like maybe I forgot panties or something, and so I figured you would be into it,” she said it so plainly. I cringed when she said that because I felt like I had been discreet. I didn’t realize that my sister noticed me looking when she walked past – I especially enjoyed it when she wore tight fitting Yoga pants that showed off her ass crack through the material.
I was a bit worried that my mom knew I was looking at my sister’s butt. I doubted my dad would be that observant, but I would die if my mom thought I was a perv like that. I didn’t respond to her question.
“How often do you do anal?” I asked.
“I told you that I haven’t been fucked for months,” she reiterated.
“Yes, you did. However, I want to know how often you do anal with a partner – one time in ten?” I asked – assuming she did one or the other.
“I don’t have any limits in bed – if a guy wants to stick it in my butt, or my mouth, or my pussy, or all three – It’s usually a combination,” my sister said almost proudly. I nearly choked. I was glad she didn’t see how shocked I was by just how cavalierly my sister admitted she took it up the ass.
“We’ll be testing what can fit in your ass,” I said as I tapped on the hole again – noticing that I could barely stick a match-stick in it.
“Okay, that’s fine,” she said without concern, adding only, “If it’s like as big as your hand, you’ll use lube, right?”
As big as my hand? Wow.
“Have you ever been fisted?” I asked.
“Yeah, by Ophelia, and I’ve fisted her – but in front of my boyfriend. It’s not like we like smelling our own shitholes. I haven’t ever orgasmed through anal, but I have had guys jizz in my butt before. I don’t really see the appeal. It’s stinky and gross, and my pussy is tight.”
I was finding it hard to think straight. I wanted to take a break and jerk myself off.
“Dalton?” Tiffy sounded worried that I had stopped talking to her. Her tone made her sound vulnerable - like she was desperate for my attention and validation.
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cat93822
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Re: My Sister the Lab Rat
I am quite fascinated by this so far, and very curious to see where it is going. Since reading this yesterday I have been slowly mulling over this, trying to work out, to decide, what is going on here and what is supposed to be motivating Tiffy.
I think at a basic level Tiffy, as someone who knows basically nothing about science or the scientific method, is doing what many people seem to do, and is treating "science" as "magic". Take one eye of newt, one particle accelerator, one blackboard full of mystic writing (algebra) and you get a magic weight loss pill out of the other end! Not really a total shock, given how science sometimes gets reported and treated.
So this leads to the assumption that "strange and random shit in, brother does some magic, I get the results I want out" is going to work. We are sort of told this after all, since she does have a list of the things she wants to achieve, but preferably with a minimum of actual work or effort on her part.
However, even having gotten this far, it still isn't all that clear what she actually wants or expects from all of this, or much more importantly, what is motivating her! As the first part went on, the possible demands and expectations that are being laid out get a lot more "extreme", and like the brother, I kept fully expecting her to simply refuse to go along with these ideas, but that never really happened.
Look at her very strong reaction to the idea of her orgasms being controlled and limited! While she expresses clear comfort with offering her body up sexually in general, and almost a desire to suffer pain, she really is not keen on the idea of limited orgasms. That is quite understandable. But what is driving her willingness to accept such a limitation, such a rule? What is the reward that she is so desperately searching for, that she is willing to accept such a price? Her brother keeps on pushing, expecting her to simply turn around and walk away, or at least seriously push back, but this really isn't happening. How come?
Yes, I know this is told from his point of view, so we don't really know what is going on inside her head, but so far I am struggling, along with him, to make sense of what is driving her. One thing I have started to wonder though, how much of this is driven by her having a significantly submissive or masochistic nature, hidden by her spiky outside? When we finally learn more of what she was expecting him to do with / to her, it is somewhat focussed on her arse and anus and on pain, so you could certainly view this as her expecting to be offering herself up in a sexual nature as payment for her desired outcome... especially when one possible outcome was turning her into a slut via mind control!?!?
So, definitely caught my interest here, and left me with a lot of questions! Rather curious to see where this might go from here.
I think at a basic level Tiffy, as someone who knows basically nothing about science or the scientific method, is doing what many people seem to do, and is treating "science" as "magic". Take one eye of newt, one particle accelerator, one blackboard full of mystic writing (algebra) and you get a magic weight loss pill out of the other end! Not really a total shock, given how science sometimes gets reported and treated.
So this leads to the assumption that "strange and random shit in, brother does some magic, I get the results I want out" is going to work. We are sort of told this after all, since she does have a list of the things she wants to achieve, but preferably with a minimum of actual work or effort on her part.
However, even having gotten this far, it still isn't all that clear what she actually wants or expects from all of this, or much more importantly, what is motivating her! As the first part went on, the possible demands and expectations that are being laid out get a lot more "extreme", and like the brother, I kept fully expecting her to simply refuse to go along with these ideas, but that never really happened.
Look at her very strong reaction to the idea of her orgasms being controlled and limited! While she expresses clear comfort with offering her body up sexually in general, and almost a desire to suffer pain, she really is not keen on the idea of limited orgasms. That is quite understandable. But what is driving her willingness to accept such a limitation, such a rule? What is the reward that she is so desperately searching for, that she is willing to accept such a price? Her brother keeps on pushing, expecting her to simply turn around and walk away, or at least seriously push back, but this really isn't happening. How come?
Yes, I know this is told from his point of view, so we don't really know what is going on inside her head, but so far I am struggling, along with him, to make sense of what is driving her. One thing I have started to wonder though, how much of this is driven by her having a significantly submissive or masochistic nature, hidden by her spiky outside? When we finally learn more of what she was expecting him to do with / to her, it is somewhat focussed on her arse and anus and on pain, so you could certainly view this as her expecting to be offering herself up in a sexual nature as payment for her desired outcome... especially when one possible outcome was turning her into a slut via mind control!?!?
So, definitely caught my interest here, and left me with a lot of questions! Rather curious to see where this might go from here.
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