It had been a long day in the lab. Formula 267.30 had taken 6 hours to prepare, and it was finally done. Now I could inject it into the test subjects and set up the camera. Then in the morning I could see if there had been any changes.

I pulled some into a hypodermics and went to the testing lab. I looked at the chart and saw that cage 6 was available. I went over and looked over the notebook on the top. Ahhh, perfect. Subject F34 met all my needs. About 10 months old, she was the only female mouse in a cage with 6 males. While not aggressive with them, she always set herself apart, not joining in the nest for sleeping but staying by herself. And other than if they absolutely forced it she would not engage in sex with any of them.

I smiled, made notes in the notebook, and gently pulled her out of the cage. A little swab of alcohol, I administered the injection and put her back in. It was like she was looking up through the top of the cage staring at me, as she went back to her own little corner.

“Oh, come on now 34, it’s not so bad. Just a little prick.” I chuckled, and then watched for a few minutes after making notes about the time, formula, and amount administered. Then I saw one of the males perk up his head from their nest on the other side of the cage and sniff the air. He sniffed for about 15 seconds and crawled out of the huddle of other mice and work his way to her corner.

I then saw a second mouse give the same reaction. By this time, the first male (number M28) had approached F34. He went over to her and after sniffing her several times he crawled behind her and got in a position to mount. Now I remembered seeing this several times, but each time F34 would react the same way. Pulling away, showing teeth, backing up so her rear was against the glass of the cage. But not this time. Her head went down, and I saw M28 mount her. And for around 30 seconds he humped her like crazy then scurried off when he had finished.

He had just moved away when I saw M103 do the same thing! And once again F34 did nothing! I continued to watch as each and every male in the cage mounted her, 3 of them twice before all the males went back to their corner of the cage.

What in the hell had I found? I was supposed to be working on a drug to help with the symptoms of menopause, that is why my subjects were females between 9 and 11 months old. This is roughly comparable to female humans between 35 and 45 years old. Ovulation stops, hormone levels change, hair follicles start to die, almost all the same symptoms, just time compressed.

But here was something I did not expect. The idea was that this could become a drug to be used in treatment of symptoms, nothing more. Hot flashes, mood swings, even loss of sexual desire maybe, these were all things I had hoped this would cure. At the most maybe alleviate hair loss as well.

“Well F34,” I said with a chuckle. “It seems that at least one symptom has been cured.” I injected the lone female mouse in each of the other cages, and each time it was the exact same result. A female that was past breeding age and therefore of little interest in sex was suddenly the center of a mousie gangbang.

The next day I pulled another sample and went to cage 9. I selected F67 and gave her the injection. Within 10 minutes the second of six males in her cage was mounting her and rutting like crazy. Apparently I had discovered something completely unexpected. As the night before, all females injected, all with the same result. They no longer fought off attempts to mate, and the males almost fought for them. Or would line up to take their turn. Sometimes returning to the sleeping area, only to return and go again.

Over the next 2 days I tested it on all 12 of my female mice. And each time it was the exact same reaction. While none of the other females were as active in refusing male sexual activity as F34 was prior to the injection, within 5 minutes the males would start to approach her and mating would commence. Each time continuing until each of the male mice had mated with her. Sometimes two and even three times. One vigorous little fucker M423 mounted F62 five times before he crawled back to his nest.

I collected up all my notes and headed home. By now I had made some graphs, which were interesting but told me nothing. Injections less than 4 hours apart had no effect. But each time so long as they were 4 hours apart would cause the same reaction in males and females alike.

On Monday I went to the “Zoo”, the basement level where all our mice were bred and kept unless they were needed. I selected 4 new female subjects, each one close to a year old or more. These were all well post-menopausal, and went back to my lab. F34, F51, F62, and F67 were removed and put into a euthanasia box and sent down to the vivisection lab as I introduced the new females to their new homes. 2 of them nested with the males, the other 2 nested alone. And there was no mating activities.

A few hours later after the lab was empty I gave them their injections. And it was the same results! Each time I injected them, within 5 minutes the males were surrounding them and pumping away with their little mousie rumps. And the females would do nothing, simply wait for them to finish.

Fascinating. Had I invented an orgy drug?

Well, it was clear Formula 267.30 was causing some kind of reaction. I read over the vivisection results the next morning on the 4 subjects I sent down. Physiology was perfectly normal for mice into their middle age. Ovulation had apparently ended in 3 of the 4, none was gravid, no apparent negative bodily changes.

The next week after much testing I sent all the mice to vivisection and selected 12 females of 3-4 months of age, and 72 males. This time the females were entering their peak breeding age. And after each injection the same thing happened. Males would mount them furiously, this time for over 45 minutes for each female, one after another. But repeat injections had to come over 6 hours apart, and repeat performances were maybe 1 or 2 times.

Were these younger females causing the males to basically fuck themselves out? I held off the next morning in cage 12, and gave the injection to cage 11. Same reaction, for almost 45 minutes the males rutted on her. I then removed the males and swapped them with the males on Cage 12.

And as soon as I put them in cage 11 they immediately went to her. Another 45 minutes of non-stop mouse sex ensued, and the female almost looked comatose at the end. The next day I repeated the experiment. But after cage 12, cages 11, 10, 9, and 8 had their way with F96 in a span of 4 hours. I then saw that she was not responding. I waited until all the males were satisfied. I had already learned that trying to remove a female during the frenzy risked getting bit by one of the males and possibly even by the female herself.

I pulled her out and laid her in an examination tray. I looked closely, no apparent respiration. I touched, no apparent pulse I could find. I checked with a stethoscope, she was dead. Good god, did they actually fuck her to death?

The rest of the week I did a more careful repeat. But now never more than 24 males for 1 female. And in all of these the females looked exhausted but recovered after 5 or 6 hours. The vivisection results from F96 came back. No obvious cause of death, not gravid, no abnormalities.

Once again another batch of mice the next week, others sent for vivisection. I repeated the experiment again, this time with males over 1 year old and 4 month old females. The males were only able to accomplish 1 or 2 matings each. By the end of the week 3 of the males had died, 2 of them “in the saddle”. All sent off for vivisection on Friday.

The latest batch had just been delivered and I was preparing for the first test of this round. This time I had 72 female mice, 6 in each cage. I was curious what the reaction of a female mouse would be to one of these with the injection. And then, I was fucking clumsy.

My phone rang as I was finished filling a syringe, and it distracted me. I ended up not putting the needle into the protective covering, but instead it went into my hand. And it apparently hit a nerve. Because instead of my hand jerking away from the needle in a reflex motion, my hand did the opposite and jerked towards the needle. And I injected myself with Formula 267.30.

I felt sick, I felt scared. I quickly secured the lab, and called my supervisor and told him I was not feeling well and had to go home. I went downstairs to my car, and once getting in I laid there for an unknown amount of time. My body felt hot, and I was uncomfortable. And even my clothes did not seem to feel right. I realized I could not drive home in this condition, so headed to the train station.

Something felt funny in my walk, and even my shoes seemed as if they were too large for my feet. I used my bank card to buy a ticket and leaned against a sign as I waited for my train. Then I saw a man come up and stand next to me. I looked over at him, he was around 40, and I think Hispanic. He looked at me, and pulled me away from the sign and had me bend over, facing the sign so I was leaning against it.

I felt my pants being pulled over my hips, and realized that they had been snug at my hips, something that should not have been. I felt fingers move between my legs, and it was ... wrong. The hand should have been grazing my balls, and instead found a fleshy area that caused me to moan into my hand when rubbed. I then felt something hard and blunt pressed up there, and thought “Oh good god, this guy is going to fuck my ass. And I can’t stop him!”

And I moaned as he slid into me. But he did not slide into my ass, he slid into another opening which was positioned lower. I felt a sharp tearing pain as he entered, then pleasure! Oh good god sweet pleasure! I rested one arm on the sign and moaned into my other hand, as feelings like I had never felt before swept through my body. Then I felt a pulsing, then the man withdrew. I gasped as he left my body, and felt wetness on my thigh. Then another man entered me. I moaned and my hand moved away from my mouth, moving down to my chest. But I did not touch my chest, I touched breasts. I felt the part of my brain still working telling me that if I had breasts, then the men that were in me and not in my ass must be in my pussy.

My pussy! Good god, I was now female!

Number 2 finished, and was quickly replaced with number 3. And I realized I was feeling something I had never felt before. A tightness in my lower belly, like an anticipation. I looked over my shoulder and say the guy in me this time could not be more than 18, and I thought he was cute. And just then I lost all control, moaning as my legs wanted to give out and I realized I was having an orgasm! But without the pulsing and jets of cum from a penis, it was unlike any orgasm I had ever experienced before.

Number 3 pulled out of me, and I knew for sure I was leaking fluids down my thigh. I saw number 1 move behind me, and gasped as he entered my body yet again. I recovered enough to look around the platform. There was another man standing a few feet away, just rubbing himself and watching. “Curious,” I thought in the back of my mind, as I realize he looked effeminate and wore eye shadow. Watching, but not wanting to participate.

The females though, that was stranger still. They were ignoring what was happening. Not watching, not turning away. It was like I was not even there, and there were not multiple guys fucking me one after the other. Number 1 finished again, and I felt somebody get shoved and another penis plunged into me. I looked over my shoulder again, it was young number 3. And after 2 minutes he once again finished, and I can only assume number 2 took his second turn.

Finally I felt no more men. I pulled up my briefs and pants, and indeed my waist was smaller and my hips larger. I tightened my belt as much as I could, and only my wider hips prevented my slacks from sliding off. I felt like a wet sticky mess between my legs, and carefully walked into the train when it arrived and took a seat. I selected one at the back of the train, it was 3 seats wide. I took a seat, and saw that the 6 men inside the car were all looking at me. And the 8 women were all ignoring me.

Then one man 3 rows forward stood up and turned towards me. He opened his pants as he walked, and when he got to me he rotated my body and pushed me onto my back so my head was against the wall of the train, my legs over the seat hanging into the isle.

He opened my slacks, pulled them down to my knees, then moved my legs so they were pointing straight up. His hips moved against mine and I looked down. Indeed I was correct, my penis was gone. There were breasts on my chest, and I looked down my body between them and saw a mat of pubic hair, and I could only assume below that out of my sight was a vagina. A vagina that the man was pushing himself into.