Gympregnation

Author's Note: My main influence for this story is probably Jukebox's Love Stinks, though I've had the general idea kicking around for quite a while.

Standard disclaimer applies: this story contains fictional depictions of erotic scenarios, so act accordingly! All characters are over eighteen, all situations are entirely fictional, and any resemblance to any real-life individuals or situations is entirely coincidental. Copyright Fidget, 2023. All rights reserved. Enjoy!

Gympregnation

by Fidget

How could they be so short-sighted?! I asked myself, slamming the door to my laboratory.

It was probably the stupid Ethics Committee, the perpetual enemy of real scientific progress. And just as I was on the verge of a breakthrough!

I had recently finalized a prototype for a project I'd been working on for three years, but at this rate it was all going to be for nothing.

I'd just have to take matters into my own hands and do it the old fashioned way, with an "unofficial" field test. If successful, I could use the results to secure independent funding, though the sources of that funding would likely be less-than-legitimate. Still, my work would live on, and I'd be well compensated.

My project was a completely original idea: a formula that increased libido and fertility in both men and women, intended for couples having trouble conceiving or with hormonal imbalances leading to a lack of interest in sex.

The more muscle mass the drug had to work with in the male subject, the greater the effects, so the most sensical and accessible location for the test would be a local gym, where the muscular subject would have his pick of available females. To ensure that mating occurred, I amped up the formula's effects far beyond what they would ultimately be in practice, and tweaked the chemistry to increase aggression in the male and submission in the female. Also, I needed to ensure that impregnation occurred in order to guarantee conception in the final product, so I made sure the formula would both disable all forms of hormonal birth control and trigger powerful maternal instincts in the impregnated female.

Once I was satisfied that the formula would make copulation irresistible to male and female alike, I drew off one dose into a vial and headed to the gym.

I liked to stay in shape myself, knowing that a healthy mind required a healthy body, and so I knew that my toned mid-20s physique clad in a nondescript sports bra and workout tights would fit right in among the gym's patrons.

I walked in and took stock of the room while I was issued a one-day trial pass, just as any other potential member would. I immediately noted that one of the trainers, a man comically bulging with a truly ridiculous amount of muscle, was walking around with a protein shake in an open cup - a perfect target.

He had plenty of mass for the formula to utilize, and the exertion generated by his frequent lifting would both catalyze the changes inside his body and increase his sweat production, the primary means by which his potent new pheromones would be released into the air. The women around him would breathe in these special pheromones which would quickly trigger submission, infatuation, and powerful physical arousal. In the meantime, his testosterone levels would drastically increase, his semen production would go through the roof, and he would find the women around him becoming much harder to resist, while also finding himself less and less inclined to resist them.

I wandered aimlessly around the gym, slowly working my way toward his ridiculous figure, and then discreetly emptied the vial's contents into his cup while he corrected another patron's form. The formula was nearly tasteless, so he shouldn't notice it under the artificial flavorings in his protein shake. I smiled to myself, realizing that he should be thanking me for the mind-blowing, uninhibited sex he was unknowingly about to have.

A few minutes later he had finished the shake none the wiser. It would take about five minutes for his body to start producing his irresistible new pheromones, so I hid myself on a bench behind one of the leg press machines to record the experiment thus far.

"Excuse me," was the next thing I heard, and, startled out of my note-taking, I looked up into the face of the very trainer I had just dosed.

Not good! I thought to myself, feeling a brief spike of adrenaline that involuntarily increased my breath rate and blood flow. Everything would be fine, of course, but I needed to extricate myself from this situation quickly to make sure the drug didn't begin affecting me by mistake.

It was a regrettable but unavoidable fact of nature that my own biochemistry was that of a young, sexually mature female, which ensured that my body's physical response to the trainer's modified pheromones would be just as strong as that of the other women in the gym. I was more than confident in my ability to recognize and resist the feelings of infatuation and submission even if I were exposed, of course, but even so it was better to avoid that situation anyway for the sake of the experiment.

"Yes?" I answered brusquely, trying to end the conversation as quickly as possible.

"Oh, sorry!" he said, taken aback my by bluntness, but recovering with an easy smile. "I just wanted to know what you were doing hiding over here." Underneath his cologne I caught a whiff of the strong tang of his sweat from working out all day.

"Oh, just taking some notes for my workout," I answered dismissively. Why won't he go away already?

"Ah, gotcha. No problem, it just seemed like you were hiding from someone, and I wanted to make sure you were ok." He was so considerate! I was glad I had picked such a nice guy for my experiment. He'd definitely take care of whatever girl he ended up ensnaring with his heady musk. Lucky girl, I thought, giving his physique a second glance. I'd been too harsh in my first assessment - his muscles gave him a bit of a dominant aura, which was always attractive in a man.

He moved to get up, not wanting to bother me further, and I suddenly felt ashamed of my initial rudeness. He hadn't done anything wrong, after all. "Wait!" I exclaimed unexpectedly, and a little too loudly.

"Yes?" He turned back, giving me a great view of his bulging bicep. Wow, I could really see why I'd chosen him for this test. His arms were thick and powerful, precisely the kind you'd want wrapped around your torso as he held you down. I blushed a bit at such a naughty thought. Where had that come from?

Either way, I had to say something. "Oh, I just wanted to apologize for snapping at you. I was focused on what I was writing and you just startled me." What was I writing? Oh yeah, notes about the test subject. The test subject right in front of me who I need to get away from ASAP.

He leaned back over me, and I sighed in unexpected relief at once again filling my nose with the pungent stink of his sweat, which finally set off alarm bells in the back of my head.

I now recognized that my body was already responding to the cocktail of pheromones he was giving off. I didn't expected it to work so quickly, or so powerfully, I thought as the temptation to stay here and continue to sniff this increasingly attractive man grew. Except I had, I recalled, because that's exactly how I'd designed the formula. I just hadn't expected that I would be the one at risk of falling under its influence. Even so, this was excellent data.

Exposed females quickly exhibit symptoms of infatuation, I calmly noted to myself, trying to resist the effects of the sour musk that was still filling my nostrils, but then I felt a tightening in my chest as my nipples suddenly stiffened against my sports bra in spite of my efforts. And physical arousal, I added wryly. So much for trying to resist the effects - in stark contrast to my mind, my body was entirely at the mercy of his enhanced virility and was beginning to respond whether I wanted it to or not.

"Yeah, no worries," he said reassuringly. "I get it. Is this your first time here?"

I saw his eyes momentarily flick down to the pert breasts filling out my tight B-cups, and, knowing that he could see my nipples standing out through the thin fabric, I felt myself gasp softly in excitement at the attention. Even so, I studiously took the time to make an additional mental note: Subject has started to focus on the sex characteristics of nearby potential mates. Subject is likely finding potential mates increasingly sexually desirable, and may even be contemplating intercourse. I shivered in pleasure at that last thought, still breathing in the powerful masculinity of his scent, and felt a tingle start up between my thighs as my vagina began to lubricate, clearly contemplating intercourse as well.

As tempting as it was to just sit and take notes in the trainer's captivating presence, I knew that if I didn't do something soon, shift his attention onto another target for his affections somehow, the situation could quickly spiral out of control. I couldn't feel it, but my body had likely already begun producing my own modified sex hormones in response to his, and they would soon overpower and deactivate my hormonal IUD. My formula was designed to make me submissive, infatuated, and fertile, after all, and I knew that I would be ovulating any minute now, putting me at severe risk of impregnation if the hunky trainer were to release his sperm into my vagina somehow. I made a mental note to have my IUD replaced once the test was over.

All the while his body would be busy dumping testosterone into his system, increasing semen production and sperm motility and ramping up his aggression, dominance, and sexual desire. In short, before long he'd be sporting a throbbing erection along with an overwhelming need to relieve that tension by filling the closest receptive pussy with his genetic information. I tried to ignore how close, willing, and receptive my own pussy was feeling at the moment, but continued to sit there nonetheless, enjoying the pleasant tingle slowly growing between my thighs for just a few more seconds. Meanwhile, my susceptible body continued to obey the enticing, procreative instructions I'd hidden in the stink of his body odor. RUN AWAY, I screamed silently at myself, but I couldn't seem to muster the willpower for some reason.

"Yeah, I thought I'd try the place out first. See if the view was worth it," I responded flirtatiously, giving him an obvious once-over followed by an impish little wink. Uh-oh. Not only did the overt flirting demonstrate just how strongly I was being affected, but it also advertised my sexual interest and invited him to respond in kind.

Sure enough, he asked "Well, do you like what you see?" and flexed his massive muscles, causing my pussy to practically gush and clench with need. God his pecs and abs were so yummy. I could barely stop myself from running my hands up and down the entire front of his body. And he smelled so good, so masculine. Would it really be so bad to let him slide his penis inside me, even just for a minute? I could surrender to my delightful infatuation with his sexy body for a bit, and let him indulge in his urge to thrust into my appealing little pussy a few times. Then all I had to do was ignore my body's instinct to let him cum inside me, overcome my growing submissiveness, and nicely ask my testosterone-addled Adonis to please pull out of my slick, silky vagina before he inevitably lost control and flooded my fertile reproductive tract with his eager little swimmers... Sigh. It seemed ridiculous that such life-altering consequences had to come from an act that was so natural and, well, desirable. It was all just so tempting all of a sudden.

My increasingly graphic daydreaming was making it clear that I'd made a grave error in assuming that I could resist my formula's effects, and I felt my skin growing warmer as my face and chest flushed with the strength of my physical excitement, especially now that he was clearly returning my interest. My nipples were almost painfully stiff against my scratchy sports bra, stimulating them further and driving my arousal even higher. The tingling in my crotch became insistent, and I had to squeeze my thighs together for a bit of relief. It was getting harder to think clearly. I knew that by this point I was grinning like a silly girl with a crush as his eyes roamed over my body more and more shamelessly, but I couldn't seem to stop myself. YOU'VE GOT TO RUN AWAY BEFORE IT'S TOO LATE!

At that moment, however, he lifted his leg onto the machine beside me, and I was suddenly face to face with his growing cock, every vein clearly visible through his skin-tight compression shorts as it inched longer and longer.

I gasped audibly. It was perfect. I squirmed with anticipation, knowing that monster would be spurting inside me any minute now. It was unavoidable. It was destiny.

Not wanting to be outdone, I began to arch my back, sticking my chest out for his appraisal. I knew that I shouldn't, but I also knew that I had nice tits, and his approval suddenly seemed really important for some reason. He must have been satisfied with them, since his nostrils flared as his breathing deepened even further and his muscles tensed to provide more blood flow to his thick cock. I shifted my stare to his glistening physique once again, all the while continuing to take deep breaths of his pungent, hypnotic scent. My mind was suddenly filled with appealing images of him restraining me with those powerful arms, forcing me to accept that thick cock over and over again, and I knew that I didn't have much time left.

But it was just so nice to stay there, letting his musk wash over me and make me hornier and hornier. I may be a scientist, but I was quickly learning that I was also very much a woman. A very aroused woman who needed to be ruthlessly held down and physically dominated by a virile man, and to hell with the consequences. I regretfully noted that I was indeed becoming more submissive, more awed by his masculine presence, and increasingly willing to let him do whatever he wanted with me. This was, again, intended behavior to ensure that the female target would compliantly allow herself to be inseminated. I felt an unwelcome shiver of anticipation go up my spine at the thought of compliantly allowing myself to be inseminated.

We had both fallen silent by this point, and were just sitting there openly leering at each other's bodies, caught up in the exciting sensation of mutual physical arousal as our reproductive organs urged us to mate. I watched his eyes bounce up and down between my flaring hips and the hard nipples on my firm young tits, before settling on the increasingly alluring gap between my thighs. I spread my legs a bit to give him a better view of my swollen vulva, standing out out clearly against the tight spandex, darkened by my vaginal lubrication. I felt so vulnerable. We both knew that I could be penetrated so easily. His cock was fully erect and visibly throbbing through his thin shorts. A bead of cloudy pre-cum soaked through. Impregnation was seeming more appealing by the second.

In an uncharacteristic moment of weakness, I stuck out my hand and slowly stroked a fingernail along the underside of his shaft.

It was more than either of us could take.

His brows lowered as his face took on a domineering frown. "Follow me."

It was my last chance to leave. Instead, I only nodded meekly, completely submitting myself to this powerful man and his irresistible virility. I could feel my own receptive femininity burning in answer, eager to receive his seed. As a scientist, I was still fully aware that my current condition had been chemically induced, of course, but as a fertile young female I was unable to resist my body's need to procreate with this powerful male who stank of pure sex.

He gripped my arm tightly, bruising me as he practically dragged me to a private massage room in the back of the gym.

The enclosed nature of the small room only increased the concentration of his tainted pheromones, and I could feel the stink of his sweat closing in around me, clouding my remaining rational thoughts even further. He crushed me against his hard, angular body and roughly pawed at my breasts while I mewled encouragement, stroking his shaft through his shorts, and then he turned me around and forced my torso down across the massage table, driving me nearly out of my mind with desire at receiving exactly the kind of treatment I deserved. He pressed up against my firm ass from behind as he held me down, and my body responded automatically, pushing back against his hard cock, feeling it nestle into my asscrack and press against my swollen, needy vulva from behind. I could even feel his balls clenching against the insides of my thighs as his cock throbbed. In my haze of arousal I thought about how full those testicles were, weighed down by their heavy load of dangerous sperm that would easily overwhelm and fertilize the egg my body had released.

Wasting no time, the trainer roughly pulled down my leggings, revealing my naked ass and vulnerable pussy to his greedy gaze. I tried to turn around, but he pushed me back down with one hand while he pulled his shorts down with the other. His massive cock and balls finally flopped out, slapping against my ass and thighs. A cloud of pungent ball musk was released into the air as his junk was freed, and the remainder of my mind clouded over with blind lust. I dumbly spread my legs, offering my exposed, dripping pussy for his pleasure, finally his fully willing breedslut. My only purpose was to have this man's babies, and his only purpose was to fill me with them.

His cock slammed fully into me with no warning and no resistance, filling me to the brim and overwhelming my frazzled mind with irresistible fireworks of ecstasy. I felt myself tense up, and then my hips were involuntarily spasming, and my pussy clamped down on his dick and began contracting, squeezing, encouraging him to lose control inside me.

His reaction to the sudden stimulation was to grab my hair and yank, hard, pulling my ass back against his hips before withdrawing halfway and slamming back in, needing more of the addictive sensation, quickly building up his pace until he was painfully jackhammering into me, holding me facedown with his powerful arms as he railed my helpless cunt.

I couldn't get enough of the pain. The sex was so much rougher than anything I had experienced before, but in my current state I wanted nothing more than to be held down and brutally used. I wanted him to force me to receive his seed, to prove that he was the one who deserved to breed me.

The trainer's artificially heightened arousal was designed to make him lose control quickly, and his gutteral moaning as his release approached sent me over the edge again. My fertile body was telling me that it was time to be impregnated, and I couldn't help but agree as my pussy clamped down on his dick and started milking. I wanted him to fill my baby-maker with his spunk, and with the testosterone pounding through his veins and my tight pussy insistently gripping and stroking his over-sensitive, stiffening cock, I knew he could no longer avoid giving me what I wanted.

With a grunt of release he began to ejaculate, slamming his heavy body fully into mine as I finally felt his thick spurts blasting painfully against my cervix again and again.

Here it comes I thought dreamily, smiling in bruised anticipation as what felt like steel clamps locked down around my thoughts. His cum had activated the maternal conditioning built into my formula, as I had known it would, and as my mind glazed over in ecstasy at his orgasm, my body chemistry made my current obsession with having his baby permanent.