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Experimental Limits (You to Tachyon TG)
🕑 Added 2025-09-11 00:05:01 +0000 UTC
“Oh guinea pig? I have something new I’d like to try.”
You sighed, halfway done folding Tachyon’s laundry, the next load of dishes waiting to go into the dishwasher as her lab/living quarters was still a mess. You had long since accepted your role as her caretaker especially after her recent retirement, some kind of bizarre experiment taking up the entirety of her free time as she had only further retreated into the confines of her lab. You wished she could show at least some modicum of appreciation, but the concept seemed foreign to her, only focused on results and the limits of everything. She could at least do some kind of self maintenance so that the room wasn’t constantly filling up with trash or at least-
SPLASH
A test tube broke against the back of your head, the shock pitching you forwards, tangling you in one of her oversized jackets as you felt a painful stinging, your fingers damp as you poked the tender mark.
“What the hell was that?! I’m not n-naaht…”
A wooziness overtook the anger, your fingers rubbing the back of your head, swearing it felt bushier than normal, thicker.
“Oh but this is something special guinea pig. So special that I might even graduate you from guinea pig to my equal, but only if this goes well.”
She hovered over you, test tubes in hand, inspecting you as you grumbled, wondering what was going to happen. It wasn’t the first time she had used mysterious chemicals on you, but they were for the most part harmless, or at least she made it feel fun, yet the more you reflected on it, the harsher the stinging grew, prickling into your skull as your whole face felt tingly. Conditioning, that’s what you had done to… yourself? No no it was only right to be her guinea pig. It’s what you wanted it’s what you-
“Is it hair growth seruhhhm~?”
Again a moan, that lapse in self control bothering you though the sensation had turned from icy to hot, your scalp humming as you pressed a finger against it, feeling the pores open and close as your vision grew crowded from unkempt bangs sweeping down. They were like stalks of muddy hay, clumping over your nose, sliding down your cheeks, your brown… Wait, was your hair color always brown? You tried to remember but that made the stinging return, pain flaring up as you decided it hardly mattered. Besides, the color made you feel comfortable, right? Similarly that lab coat you had been folding did feel rather nice against you, still warm from the dryer, like a nice portable lab whose pressure could always make the world feel smaller as you slipped it on without a second thought. After all it was yours wasn’t it?
“That is one of the side effects, though this is just the primer. The real fun starts once it’s imbibed orally, guinea pig.”
She held up a tube so pink in its coloring it was downright luminescent, an aroma so powerful it overtook the trash laying about of to-go containers and crumpled up research notes.
“Whywooulliiiii-“
Great, you had a real bad case of mealy mouth, your head trembling as you took stock of things, your heart rate elevated, palpitations frequent as a sheen of sweat stung your eyes. You felt hot, much hotter than usual and your tongue was like a thick slug as you worked your jaw, everything clicking as you ignored the back of your head to massage your cheeks.
No wonder you felt so odd, just a bit of circling pressure enough to make the bones lock back in, your cheeks flushed as you dug your nails into the stubborn stiffness, working it all away as you nearly reached your limit of sensation overload.
There was a rough throbbing in your temples as you squashed your tongue against the roof of your mouth, feeling something bitter dribble down your throat as its bloated form shriveled like a sponge being drained. It was such a fun sensation that you couldn’t help but do it repeatedly, teeth bristling as they felt harder, smaller, better… Perhaps there had been a serotonin propagator in there? Wait, why did you know that terminology? You had gone to school for-
CRUNCH
“Uhhhhngh… Wh-Why wouldn’t I want to try one of ou- your amazing experiments?”
You felt like that wasn’t what you had wanted to say initially, but whatever had been the original intent had been suppressed, reaching out with your hand only to pause at some irregularities. It was hard to see clearly, your eyes stinging from sweat and a minor, yet notably discomforting bubbling inside the jelly, chaotic sprouts of lashes not helping as your vision blurred.
There was something definitely off about your fingers, some of them blocky, other svelte, the tactile rubbing quite pleasing as supple skin scraped against rougher, hairy digits, the nails appearing as if they were growing, nail beds tingling as you felt pressure on the thicker ones. Such things could cause you to drop such integral research, that worry far more important than any visual oddities, your hands clasped together as you cracked your knuckles, each joint popping in a stimulating fashion that calmed down your doubts and made your thoroughly stiff member throb.
“Hehe gimme gimme gimme~!”
“Quite the eager guinea pig aren’t you? Won’t have to be too coy for much longer.”
You didn’t get the hints she was laying out, too focused on the lovely aroma wafting through, your slender instruments of science eagerly grabbing the test tube as your nose flared at a concentrated dose, eyes watering as the sclera darkened to a vibrant red. You wanted it, needed to be a good guinea pig, knowing you’d finally graduate like an abused undergrad who finally filled their core credits, lips damp and thick with saliva as your nails tapped against the glass tube.
Down the hatch it went, fizzing like a heavily carbonated soda, the flavorless serum not needing a distinct taste, the sensation of its existence enough to satisfy as you could feel it slide down your esophagus and bubble inside your stomach, everything trembling as your body felt chills and tingles all over.
“NNGH?! Ohhhh UHHN H-AHHH~!”
You tried to restrain the cries but it was so powerful, throbbing in your temples as the potency of the drug had its way with you, making you a helpless observer as you struggled to your knees. It wasn’t just your temples, something stroking your brain as it shifted, two spots of condensed stinging on either side of your skull. It was like the serum was swallowing you, the sleeves of your lab coat pooling against your palms, slipping over, your fingers disappearing as crunches and pops numbly rippled through you. Surely that couldn’t be real though, such abnormal physical shifts bound to be painful, and you felt so good you were barely holding back the hot gush of testosterone yearning to break free.
“Good, good guinea pig. Now I need to check its effectiveness. Please think in concrete terms, who are you?”
“Mmgh gahh!”
The throbbing worsened, that stabbing chill drilling deep into your thoughts, scraping each memory, your scalp audibly pulsating as Agnes began fondling them. You shuddered, thighs clenched tight to stopper your pleasure, the pain doing little in the face of her repetitive strokes, counting each one as you felt more and more of our brain being scraped. Training, hometown, human, male, all these ideas hurt to think about, feeling so real, as real as your hands sinking into your sleeves, watching them droop, the room rising around you as your sunken grip fumbled with the tube and spilling it all over your shirt.
“Ahhh Ahhhgnes this issnnngh I-I’m-”
“43, Oh dear 44, guinea pig. 45, Hit your limits 46, already?”
You tried to say yes only for her fondling to suddenly grab one of the pressure points and pull, those memories slurped up as you came, the pleasure finally breaking past your restrictions as she fondled the inside of your twitching horse ear. The serum, i-it had to be amplifying all sensation, all reality, your mind barely coherent, flashes of irregularities crashing together as you slumped backwards, so much raw data pulsing out your cock as you tried to contain your bliss from Agnes’s ear rubs.
“The hallucinogenic is strong right? I bet you thought those memories were real guinea pig, yes? Or does that feel wrong?”
She had a manic smile, your eyes heavily lidded, that wrongness growing as you could feel yourself shrinking, the other lump unfurling with every throb as you tried to gather your evidence that something in this experiment wasn’t right. Hallucinogenics? All those memories of not being a musume, of being a trainer, all those experiments? Wait were you the one being experimented on or were you running it? Ah yes your precious guinea pig, oh how delighted you felt making him squirm or n-no you loved being her trained, obedient test s-subject… You grunted, more of your forehead squeezing down, Agnes merely rubbing the rising nub of flesh that felt so familiar, ears coming in sets of two so it made sense you’d have another-
SPLURRRT
“G-haaaaawd oh ooooh yeah…”
Your nose released alongside your cock, the stubborn brain matter bursting into a fine mist of blood out your nose, the dizziness making your head droop as you watched your ill fitting trainer’s uniform shift. Definitely some kind of concentrated LSD in there, the stitches writhing like vines, yellowing as a bit of you panicked over soiling yourself. You were unloading unquantifiable amounts of fluids, but no it was your normal attire wasn’t it? Your favorite v neck sweater, the thick collar of it draped over a darkening dress shirt. It tickled, the cloth was rubbing against your body like it was teasing you or giving a thorough checkup, the stimulation allowing a few more spurts of release from your nose as whatever was bothering you had vanished.
“I’m hiiiiiigh~! As a kiiiiiiiite~!”
You were moaning identically to the pleased squeals of your… mistress? Owner? No no something was welling up inside, a need you had to-
SQUISH
“Ahhhhn w-waaait my p-huulse is elehhhvating ohh these palpitations these NNGH ohh~?”
Tachyon’s hands were on your chest, her heavy breathing making your valve drip once more, her sleeves swiping in her constantly shifting focus as she rubbed your core through your shirt. Each tweak of your braless nipples(did you forget to put one on today?) increasing the muscular spasms within, palpitations almost feeling like a burst aorta as such violent, hot fluids sloshed inside.
“All within our parameters. Surely this isn’t the limit of our growth now is it? This is very serious work. I must make sure our physique is coalescing properly.”
You were starting to understand, her fondles targeting specific muscle groups, your core a bizarrely gurgling mess since you had downed the serum, the nauseating churns of stomach acid and organs sounding like progress as your arousal rose, your cock no longer enough to contain it as that welling sensation amplified in your chest. Staring down there were loose folds of fabric, your pitiful a cups hardly correct. Had you been modifying your fat to muscle content again? You gave the throbbing peaks on both a rub as the room spun, thicker secretions pulsing out your valve as the internal knobs loosened, the pleasure truly unquantifiable as you pulled on the sloshing, growing mounds.
“Good Agnes, I’m making sure our abs are restitching nicely, hard to focus on multiple tasks at once like this. We both know how worrisome a muscular tear can be.”
You gave a pleased whinny, being called Agnes radiating such warmth, no longer a guinea pig, new limits tested and broken internally as your original molded your waist, snapping vertebrae, guiding in ribs, condensing all that bulk that must have come from a failed experiment into steely supports as you could feel your blood flow improving, your half hyperventilated whinnies really filling your lungs as your tits bloated out to their full potential.
But you weren’t done now were you? Your innards doing flips as Agnes continued to prod, your core and top heavy balance ill fit for the current sway, far too top heavy as your hands slid downwards towards your ass. You smacked it, the muscle far too stiff and blocky, inflexible really, obviously out of sync with your superior upper half. Had sitting for too long caused gravity to squash your curves? Had you even had curves before? You wrinkled your brow, another bout of angry stinging deep inside your cranium that promptly turned to bliss as you dug into the blocky cheeks.
Yes it hardly mattered what had come before, you had to make it better didn’t you? More aerodynamic, more plush, perfectly calibrated to offset the forwards drag of your heavy tits as you squeezed and squeezed till another orgasm further ruptured something deep inside, your hands clenching each burgeoning curve and pulling out, not stopping till your pelvis gave into your demands and spread into the most optimal configuration for your hourglass, as precise and measured as any you’d find off a factory line, your eager whinnies so much louder as your diaphragm shifted to match that beguilingly soft tummy, your slender waist perfectly arched to work with loosened shoulders to twist and catch each gust of wind to the margins of perfection.
“Excellent work Gui- Eh hem Agnes. I have to get used to that now, but now comes the moment of truth.”
Her fingers made yours feel downright amateurish as she felt up your hips and ass, a few brushes and squeezes enough to make you hit your pleasure limits once more. You knew what was coming next, not even phased as she brought out a small spray can connected to a test tube that quickly emptied into the spray on pantyhose fluid, your legs already tingling, but extra saturation couldn’t hurt at this point. You shimmied back, lifting your bulky legs, both of you eager to see if it would work as hypothesized as she pressed on the nozzle. It felt cool on your hot skin, bonding like a second dermis as she coated your thighs and calves, shaking every now and then to keep a consistent layer, finishing off with your feet as the liquid clothing began to settle.
As it dried it grew tighter, a slight burning sensation following the frictional rubbing as you could tell your hairs had all been scraped off, the entire process making your legs ache, muscles squirming, the ideal mold of your most important features continuing to tighten as simultaneous charlie horses painfully rippled through your supports. Agnes could see the clear discomfort, your thicker, bulkier legs also substandard for running, the muscle and bone needing to be condensed and collapsed into the proper forms.
“Don’t worry a bit of pain is its own form of stimulation. Imagine it’s the lactic buildup on the last stretch, that pain the barrier to surpassing our limits. Would we give in?”
You shook your head, moaning as her hands began to feel up your legs, adding to the squeeze, so much muscular structure shredding and knitting tighter, the cycle of squeezing, rupture and reformation saturating every piece of your brain as groans of pain and bliss merged into a constantly shifting utterance of nonsense.
You could feel the lipid structures squirming out, the stuck pantyhose pulling on your thighs from every direction, Agnes smacking any stubborn patches as such lush padding cradled your cracked test tube. Such padding was crucial for protecting the strength inside, squeezing on the leaner muscle underneath, folding it over and over as inches of height were pancaked inwards, an urge to smack them together turning to a nice cycle to expend all that nervous energy from being such a passive test subject.
“Applauding my efforts?”
“Our ehhhfforts MMM~ Tahhhchyahhhn~! Ohhh~ haaarder the pain! Nngh it’s condehhhnsing ahhgh AHHH~ AHHHHLMOST TH-HEEEERE~!”
You had to contain your excitement, the thickness of your thighs a perfect stopper for the leaks below, Agnes’s fingers rubbing up and down your calves as pain ripped through your main supports. Precious calcium and spare ligament were bolstering the source of your limitations, the pain flaring as she worked the mass down, that charlie horse shrinking to more of a pony, then a guinea pig, her thumbs digging into your feet as you as they arched into perfectly trained kickstarters.
Yes you could feel it, the muscular tears and inner fractures knitting together, your ankles flexing, toes pinioned as all their spare mass went into healing the shredded mess you called an ankle. All the swelling was squeezed, the last of the pain welling over into healed, optimized bliss as you came, Agnes similarly reaching her own limits at the sight of success as the two of you whinnied in identical pleasure. Your limits had been shattered once more, rolling your feet, feeling the firm yet flexible stretch of knitted tissue, the tension wonderfully flexing your hamstrings as you felt whole, complete. Your retirement thesis had been retracted as the new data proved itself to be true.
“I’m ready to return to the track and break every limit we’ve-”
“Not quite other me. There’s still one last matter to resolve…”
“Oh? What could possibly- GAHHH!”
Even as she was shaking off some dampness on her own pantyhose, Agnes was quick to flash a pair of scissors, grinning madly as she began cutting through your shirt, unfurling your spandex shorts and pantyhose as you tried to shake her off, confused at what could possibly justify such perverted destruction of your favorite-
“We have to take care of a bit of drag. Oh dear, is some of that guinea pig still in you, Duplicatachyon? Stop squirming, we're nearly finished with our experiment and I wouldn’t want to scare you ourselves.”
Drag? Guinea pig?! Urgh the painful tingles were flaring again, some small throbbing resistance bubbling to the surface. Why did this feel wrong for a moment? Not physically, the serotonin and adrenaline leaving you constantly trapped in the peak of heat as if it was mating season, but ethically and morally which… wasn’t… how you… were supposed to… feel? Barriers were meant to be overcome, questions answered and limits broken and yet you could vaguely feel some semblance of being someone else. Ah th-the thought of being overcome by Tachyon, of having your brain so utterly ransacked, it was turning you on, making you so sopping… hard?
“Ehhh? Why do I have a… No I’ve always h-had AAAAAA~”
Agnes swallowed your entire cock in her moe sleeve, her fingers wrapping around your shaft and stroking suddenly, the depleted source clearly still not at its proper half life yet as soon it was throbbing with energy, your nipples stiff and large, your bloodstream coursing with half mutated testosterone as you felt oddly emotional at the idea of losing it.
“As much as I’d love to experiment with the first stallion of our kind, musume’s must be mares and besides such a large source of testosterone would count as doping, not that we care about that much if we could just get the guidelines loosened imagine how much further we could train our muscles and how many records-”
She continued to yammer as she stroked you off, your naked form trembling, an internal clench building as your cock could barely hold on, both your balls suddenly pressing against your innards as you came even harder than before. Agnes paused a second, raising her non-stroking hand to check a stopwatch and nodding at her findings.
“One full minute. Surely we can cut down on that? After all it’s not good to have such a dangly mass of lag flailing about as we run, why just imagining our thighs scraping this thing could lead to all sorts of unforeseen problems. Why, this sack is so unguarded I might as well make an improvement.”
You couldn’t see the specifics but you sure could feel it, any aversion shrinking with the inwards thrusting of her strokes, that guinea pig mentality and morals all squirting into her sleeve as you could barely hold back the next squeal. She was slamming into your balls, the exact moment of impact changing subtly as you could feel something worming inside, the sleeve hiding it all beyond the pure tactile-
SQUISH
“AHHHHN AHHH OOoooh…”
“Thirty seconds. Much faster. Isn’t that better, me?”
You could feel the drag lessening, part of you excited to become even the slightest bit more optimal, even the resistant source of it aching wonderfully, still stiff at the thought of its own betterment, your mind filling with the possibilities as she continued to stroke, each motion getting faster, or was your race track getting shorter? Yes it was, a marathon gradually shrinking into a sprint, your hands mimicking Agnes’s jerks as you could imagine the motion, the thrusting, feeling it push and push and-
“Twenty seconds, viscosity lowering, elasticity fading, recognizable features flattened into a smooth tube.”
Yes yes yes the more she pressed the faster you could feel your own testes racing down internal tracks, a perfect tie as they crossed their separate finish lines, femininity the dominant internal emotion as you could feel the estrogen bubbling-
“Nine seconds, very nice progression, secretions slick and slippery. The tip seems to be opening as structural integrity collapses. Inserting one finger into-”
What had you possibly been worried about? Such marvelous data, such plateaus of pleasure being burst through and shattered as you could only moan and scream and beg for her to keep going, keep making you-
“Three seconds, finger being sucked in, entire shaft opening, subject eagerly thrusting to hasten- Oh two seconds? Hey wait you keep- Two seconds I can barely note- One second one second one one one-”
POP
“ZEEEEROHHHHH OHHHHH OHHHHH~!”
They chained repeatedly, the scent of sex filling your jointly owned lab, pure scientific fulfillment radiating from below as her sleeve finally separated, revealing a fully articulated slit as your labia swelled, all drag finally eradicated as you made it a point of pride to remain standing as you came your metaphorical brains out. After all, if something as trite as five orgasms in quick succession could make your knees weaken then what hope did you have at a triple crown? Soon you were self analyzing, gasping as you willed your heart rate to slow, your gleaming body to cease perspiration, ignoring the puffiness of your nipples as those weren’t going to soften any time soon after such an all encompassing thrill.
“Experiment complete. Ahh it feels good to be the one saying that for once, though I remember saying it every other time as well. My what a lovely feeling. So are you ready for your turn?”
Her twin nodded, popping calcium pills and a blended mix of proteins, meat and vitamins, Duplicatachyon unstoppering one of the test tubes in her jacket and waiting for her original to swallow before jamming it down her throat.
“Wait, I had backups of Rice Shower and Jungle Pocket as well for the testing phase. Which one did you graAAHRGLE GLLB GUUULP~!”
You giggled, enjoying watching another you sweat and tremble, her bandaged leg flailing as not even you knew which you had given. Either way it would be a wonderful experiment, the birth of a new guinea pig, a new maid or a rival equal to your ideals, the original beginning to moan as her own manic high began. You were utterly sopping, excited to collect more data, gain more notes, test the limits of the original’s identity if the wrong vial had been chosen. You were the dominant one now, the experimenter, and you couldn’t wait to start seeing some results.
“I suppose we’ll have to find out now, won’t we Guinea Pig? Now, please tell me how it feels and try not to let it happen too fast. I absolutely need more data. Experiment start!”
