[TFTG, MtF]

[CW: Consensual, Free Use, Explicit Scenes (Sex)]

“Why’d you even make it? Seems pretty random for you, but so do most of your inventions…”

My roommate turned his whole body to look at me. “Look, there’s a lot of people out there that weren’t born in the right body. Transgender people, ya know? And not just the ones that have everything figured out. There’s a lot of ‘eggs’ out there that are questioning things about their gender and sexuality all the time. Now, imagine if there was this thing they could drink and be the opposite sex. Permanently, temporarily, it doesn’t matter. Think of how many people would be happier, and how many lives it could save from depression, or worse.”

Well, at least he had a noble reason for this, I supposed. I looked at the bubbling multicolor solution on the table skeptically, and then at my roommate with both skepticism and concern. “How do you know it won’t kill you?” I asked, tilting my head to the side.

He chuckled, shaking his head. “Mike, it won’t, I promise.” Apparently the look on my face wasn’t very convincing, so he went on. “Look, I made it myself, I know everything that’s gone into it.” Turning his focus back to the lab bench, my roommate began adding a few more chemicals into the mixture.

“Drake…” I started, but I was cut off before I could seriously express my concern.

“Mike,” he replied, using my own name again to stop me in my tracks, “it is fine. It’s just a solution of proteins that target DNA to make some basic changes, some compounds to damage all my cells and make them regrow with the new instructions the proteins included, and a liberal dose of painkillers so I won’t feel a thing.”

“Damage all your cells? Liberal dose of painkillers? You hear how horrifying that sounds, right?”

Drake sighed, turning around with a vial of the seemingly magical fluid in hand. “We’ve lived together for, what, three years? Four, now? You’ve seen my inventions firsthand, you’ve even benefited from them yourself. Has anything ever gone wrong?” I sighed, and shook my head. “Exactly,” he continued, pleased with my answer, “and that’s because I know what I am doing. Just trust me on this, pal. I promise this won’t be a problem at all. Now, do you want to watch me turn into a girl or what?”

Before I could protest again, Drake had already chugged the entire vial, leaving it bone dry empty in the process. I stared at him, mouth agape, unable to process what I just saw. My roommate was never the kind of guy who would slam back a shot or chug a beer, but I never thought of him as the kind of guy that would throw away his manhood so casually.

I watched him for a moment, waiting for anything to happen. I wasn’t sure what I expected, perhaps that like some sort of magic trick my roommate would disappear and a hot girl would take his place. But nothing seemed to happen, until my roommate let out a surprisingly feminine giggle and hiccuped.

“Should be starting soon, at least, the painkillers have kicked in,” he whispered. I stepped closer, both to hear him, and to catch him should something go wrong. It wouldn’t help for the household genius to hit his head on the cement of the basement floor, and knock away via concussion any hopes of fixing himself.

The changes started subtly. If I wasn’t watching for it, I would have missed it or played it off as a trick of the light. What really alerted me to it was that my roommate wouldn’t stop scratching his head. Drake’s hair was a lighter color, and longer. He always had a particularly shaggy cut - his nearly jetblack hair draping around his neck casually - but suddenly it was a bit more of a dark auburn that reached to his shoulders. As it lengthened downward, creeping and crawling down his back, its shade was getting progressively lighter. By the time it reached his waist where it seemed to stop its journey, his hair was entirely red, with faints locks of dark blonde and brown running through it giving it a shimmering tone.

Drake went to chuckle, but based on the surprise in his eyes and the way his hand shot to his face, I could only assume that his jaw didn’t feel the same way it had felt his entire life. Just looking at him, it was only clear why; all the little details and underlying anatomy of his appearance were gone, totally replaced by someone else’s. Bones pulled and pushed into new positions, and overall his head diminished in size, shrinking down to become one fitting for a smaller body. The birthmark on his cheek slowly faded away as it became similar to the skin around it, all smooth in tone and flawless. For a moment, I thought he was slightly sucking his cheeks in, before realizing fate had now granted him dimples that this magical transformation process pulled in on their own. Even the shape of his eyes shifted subtly; instead of a narrow gaze with eyelids drawn closer together, his upper eyelid seemed to pull slightly upward while his lower lid retreated in its own direction, giving his gaze a brighter, more wide-eyed look.

He no longer looked like his normal, male self.

He looked like a woman.

Or at least, he had the head of a woman. Fuller lips, strong cheekbones, a more angular shape to his face. His eyelashes were naturally full and dark, and it appeared this serum gave Drake sculpted eyebrows that any woman would die to have naturally. His blue eyes, normally ice cold and calculating, were now large warm amber spheres that were inviting to look at and gave him an innocent and naive gaze. Without realizing it, I took a step forward, my hand raising slightly. It was like a magic trick, but like all of Drake’s inventions it was just a science I didn’t understand.

“It’s ok, you can touch, I hardly believe it either,” Drake whispered, his voice soft despite how little distance remained between us. I realized I was looking down at him slightly; normally we were at the same height.

“You’re shrinking.” I felt silly stating the obvious, but at least I said something. My fingers had found their way to his face, an action I didn’t remember taking. His skin was soft, smoother than I would expect a man’s skin to be. I had to remind myself that, if this formula is working, this wasn’t a man’s skin I was touching.

“Wha-?” Drake coughed, and it sounded wet. For a moment, my panic rose up as my hands flew to his sides, ready to catch him if he fell. He coughed again, and then smiled with his new plush lips, golden eyes twinkling. “I… I think that was my voice changing.”

He was right, of course. His voice sounded soft and gentle, with a soft lilt at the end of his sentence. It was feminine, and perfectly matched the girl he was becoming.

I watched as my roommate’s changes seemed to take a pause, his body slowly getting shorter and shorter. His clothes were practically falling off him, and I stepped back to let him shed his normal clothes and his lab coat. All that remained adorning his body was his boxers, even though they too were a size much too large already. He stepped closer to me, closing the space. He was a head shorter than me.

‘A girl this tall would be perfect to cuddle,’ I errantly thought, before chastising myself internally. Drake was about to be a girl this tall, and I already was thinking about cuddles. I had to remind myself this was my male roommate, first and foremost.

Reminders like that were almost immediately rendered impossible. Drake apparently felt the need to test out how sexy his new voice with a slow moan. Giving him my best look of bewilderment, he meekly gestured to his chest.

“Sorry, dude,” he whispered in the voice of an embarrassed girl. “It just… feels so good.” I bet it did. Instead of meek little male nipples, Drake was now sporting the much larger feminine version, complete with large areolas that clashed in color with the surrounding pale skin. Based on how hard, throbbing, and twitching his nipples were, it was clear how good it was feeling.

Quickly, Drake shot his hands up to his chest and covered himself. The moaning returned, except it was louder and more rapid this time. I watched in amazement as Drake’s hands were pushed away from his chest as the underlying tissues began to swell and multiply in size. Breasts… Drake was growing breasts. The efforts most girls would look forward to and then endure for years during puberty was happening within moments for him. I watched as cup sizes flew past for Drake, trying to ignore his sounds of pleasure and the effects they were having in my pants. By the time he had finished growing, I could only guess his cup size at a D or DD, based on past women I had been with.

I would have said that his chest was a handful, but not too much so, but that would have only been true for myself. As if his body knew what his hands were doing, the changes had progressed down his arms in secret - shedding all unneeded body hair in the process - and reached his hands. They were smooth, thin and dainty. Despite being smaller than they were at the start of the process, Drake’s fingers looked longer, making up a larger proportion of his hands.

The changes continued sweeping down Drake’s torso. His waist pulled in at the sides, and even while his hips remained male, it looked like he had quite the hourglass figure. Once his hips began swelling - this time with only a pleasurable sigh from Drake - the appearance was complete, and my roommate had the shapely figure women would die for. It didn’t hurt matters that his ass was as full and bouncy as his chest was, especially now that Drake’s hands were preoccupied with all the new changes.

There was only one problem, a problem that had Drake dancing from foot to foot in as much discomfort as the painkillers in the serum would allow. The boxers were now stretched tightly across Drake’s hips and his new rear end, so tightly that his male genitalia was being crushed against the front. With a few choice curse words, Drake stripped off his boxers, exposing himself to the room.

Either the serum hadn’t touched his member yet, or he was well endowed enough that it didn’t make a substantial difference yet. Eventually, we both watched as my roommate’s cock slowly retracted into his body, millimeter by millimeter, while his balls slowly shrunk away in the ever dwindling sack they found themselves in. Drake, for his part, was trying his best not to make the situation awkward and was containing his moans and whimpers as his most sensitive bits were being rewritten and reworked into a new configuration more in line with the form he was taking on. Despite his best efforts, though, his hips bucked forward and back while his toes curled. It was clear that he was having a strong orgasm just from the changes even though no semen was leaving his body. Slowly, everything of note down there disappeared, and for a moment, there was just a flat expanse of pale skin. Eventually that changed, as an impression formed in the flesh, and a cavity started forming.

Drake wasn’t able to keep his composure any longer and cried out in lustful pleasure. I glanced up at his face, and was shocked by the wanton expression of lust and passion mixed with surprise and hesitation I saw there. Drake’s lips parted and his eyes rolled back, silently riding out his pleasure. For a moment, I considered how it was similar to looking at a girl during her first time before I realized that was exactly what it was. Drake now was a girl, and this was her first orgasm in her new body. A body that had staggered back toward the cold concrete walls of the basement as Drake panted and groaned in pleasure. The whole sight was alluring: a naked girl - skin shimmering in the sweat of passion - trying to catch her breath after being torn apart from her orgasm.

Without realizing it, I had stepped forward until I was nearly pressed against her body. I stared at her face, captivated by the eyes rolling back in pleasure and the mouth held agape with a cute bead of saliva teasing at the corner of her lips. Gone was the all male form of my roommate. She’d done it, her genius had come through again. There was a smoking hot babe in front of me, naked and aroused, so I did what every guy would do in that situation.

I kissed her.

She was surprised for a moment, the haze of her pleasure making it hard to think through what was happening. But once those seconds passed, she returned the kiss with vigor. After long moments, we broke the kiss and looked at each other, before bursting into giggles. She pressed her body against mine, her head perfectly snuggled under my chin. Finding the opportunity presenting itself, I held her ass in my palms, finding it so perfectly soft and squeezable I regretted not doing that soon.

After a few minutes holding onto each other like that, Drake had ridden out the last of her orgasmic aftershocks, and looked up at me with her radiantly glowing face.

“Hey, so uh… I guess it worked?” The way she phrased it sounded like a question, but I knew she was looking for a way to start our conversation back up.

“Yeah, it did,” I replied, a chuckle in my voice. “Drake, about that kiss…?” I started to apologize, unsure of how to go about explaining myself.

A giggle that sounded like a melody was the response to my question. “Don’t worry about it, Mike. I didn’t just invent this serum to have a female body. I want to see what female life is like, even the parts that involve touching and sex.”

The way she said it so nonchalantly blew my mind. Sex. There weren’t many options for who she had in mind, so clearly she meant it with me. After a moment’s pause, I realized that that didn’t bother me, at all. As roommates, we’d always been close friends, and now that our sexualities and sexes were compatible, it made sense to take that friendship and make it more of a friends with benefits structure. This was fine with me, and apparently it was fine with her.

“Oh, and don’t call me Drake. I’m a girl, let’s have a girl’s name for me. How’s… Diane sound?”

 ===

“You actually wrote up a statement before you took this serum?” I held the sheet of paper in my hands, looking at it incredulously.

Diane shrugged and sat back on the couch. “I didn’t want you to think that I was being influenced by the changes, or anything like that.”

I took a moment and looked over at my roommate, my breath catching in my throat. The first thing I noticed was her clothes, or rather, lack of them. It turns out that back when Diane was still Drake, he didn’t know exactly what size or shape he would end up as once he was fully a girl. Diane’s solution to this problem? Solely wearing her various lab coats, which came down to her knees anyway and could function as a makeshift dress.

If only she’d button it up, then it would be a dress. Unbuttoned, it was causing me problems. Well, just one problem: it was constantly turning me on. There Diane sat, lab coat only loosely drawn around her body such that her breasts were fully on display, nipples proud and hard in the cold room air. Not only that, but she still sat like a guy; despite having nothing between her legs to cause her to sit spread open, she still did, and her always-glistening sex made my own consistently hard. It was like she was intentionally trying to be the sexiest tomboy in existence, a theory that delighted the more primal parts of my instincts.

I swallowed, turning back to the document. It was simple, saying that Drake-as-Diane was ok with any and all activities two consenting adults might get up to, providing her consent in advance. It also had an interesting clause in there about how she was consenting for things to happen without any further discussion.

I looked up at my roommate, struggling to maintain eye contact. A struggle that ultimately failed, but if Diane noticed my gaze passing over her curves and soft flesh she only showed it through a slight uptick in her smile and her dimples growing ever slightly deeper. “Fine,” I said, managing a smile that I hoped wasn’t just made of lust. “I accept that you thought this out ahead of time, and that you want the full feminine experience - no holds barred - and that you want to have those experiences with me.” I let out a soft chuckle. “I promise I’ll do my best to make it happen.”

She chuckled and clasped her hands together, beaming at me. “Awesome, dude.” It was a little strange, hearing exactly how Drake would talk through the sweetened voice of Diane. Only roughly a day had passed since I watched the transformation - during which Diane mostly kept to herself - but already it was starting to be difficult to think of this person as a person that was once a guy.

Standing, she shrugged off her lab coat. “Well, I don’t need that anymore, now that you’ve agreed and read the statement.” The cold air of the living room immediately sent a shiver through her, her skin peppered with goosebumps. I couldn’t help but stare for what felt like minutes until she finally walked over to me and whispered in my ear.

“Remember, any time means just that, any time.” Her voice was breathy and immediately I went hard. Had she been practicing that while alone yesterday? I choked and fumbled my words, my eyes locked on the breasts swaying in front of my face. She giggled, her mission accomplished, and walked out of the room and left her very frazzled roommate to figure out what just happened.

At least, that was her plan. I decided enough was enough, and that two could play at that game. Before she got more than a couple steps away, I had already stood, walked up behind her, and grabbed her ass firmly. She yelped and moaned, looking back at me.

“Leaving so soon?” I whispered in her ear, watching the chill run through her body. I doubted it was the cold this time, and I pressed my advantage. My fingers slid between her lovely thick thighs, brushing against her wet slit. Damn, she was as horny as I was. I smirked, leaning forward to nibble on her ears. She made a cooing sound I just loved, and I couldn’t help but to give her rear end a spank.

Diane jumped and looked back at me. “What was that for, Mike?”

I curled an eyebrow up. “I’m doing what I want to do, isn’t that what your agreement said?”

After a moment of internal deliberation, she nodded and grinned. “Yeah, I suppose it was.” With that said, off she pranced back to her room. I watched hypnotized as her hips swayed from side to side, making her curves and bounce and jiggle seductively.

 ===

I was in bed later that night when suddenly my door creaked open. The vague silhouette of a woman slipped into my room, closing the door behind herself. My bed creaked in protest as she slipped under the covers next to me, the two of us laying on our backs.

“I was cold…” she started, trailing off. If the lights were on, I’m sure Diane would have had a shy smile on her face.

“You know, most girls sleep with pajamas or a nightie on, or something. Helps them stay warm.” My voice was gentle and teasing, and I felt a gentle slap against my chest.

“Just a habit from being a guy, I guess. A guy’s brain in a girl’s body, I guess that makes me more of a tomboy, huh?” Fuck she knew how to push my buttons I didn’t even know I had. I was rock hard, praying she wouldn’t notice. Moments later her entire body was pressed against my front, ruining that silent prayer. I reached a hand up without hesitation, fondling her rear end.

Things were quiet and still for a moment. Perhaps she wanted to sleep? Perhaps she wanted more? I took the opportunity into my own hands, rubbing my hips - and my bulge - against her front. Diane responded quickly, using her slender fingers to guide my sex against hers. Nothing much happened for a long moment, both of us holding still and quiet in anticipation. Suddenly, the tip of my member popped between her lips, and with a shared groan my length started to slip into her.

The air was filled with panting and soft moans to each other as we had sex for the first time. She rode me from the top while I put in equal effort from the bottom. It felt freeing, being with my best friend in such a manner. No strings were attached, no obligations. Just two horny people both really wanting sex with each other.

My climax came, and I filled Diane’s virginal sex to the brim with hot seed. The new sensations were enough to push her over her edge as well, causing her entire body to writhe atop mine. Once the majority of her orgasmic waves had passed, she collapsed on my front. We were still and quiet, and after a moment Diane’s snores were the only sound in the room. I smiled, pulling up the blanket over us and falling asleep with her.

 ===

Most people would expect there to be an adjustment period after such a life changing moment. After all, within a day we had gone from a pair of male best friends to being gender-crossed lovers. One of us had grown tits and ass, while I was constantly draining my balls into her.

Surprisingly, it was all going smoothly. No one had awkward moments where they said “I love you” to each other, which was my biggest concern. It’s not that I didn’t love Diane, but we were  best friends, now with benefits. There weren’t any strings attached to this whole situation, and neither of us were falling for each other.

One morning, after a couple weeks of this new lifestyle and arrangement, was arguably the first problem we actually ran into. I came out of my bedroom - though lately, it had been our bedroom to share every night - and found Diane sitting on the living room floor sobbing. Immediately I rushed over, putting my arms around her.

“What is it, Diane? What’s going on?”

As soon as she heard my voice, she looked up at me. Her makeup - a skill self taught since the change that she was already pretty talented at - had started to run, streaking down her face. She sniffled, looking up at me with her large amber eyes. Fuck she was hot, even when sad, I thought to myself.

“Mike… I’m… it hurts…” She gestured down to her lower abdomen, holding her hands softly over herself. I looked confused for a moment, until I realized she was wearing boxers again, with the distinctive shape of a pad put into them.

“I…” Diane continued, barely even whispering, “I’m having my period…”

I stroked her hair, pulling her close. “Isn’t this a good thing? You know your serum fully works, and you wanted the full experience, right?”

Another sniffle as she nodded. “Yeah but… oh gods, why does it hurt so much! And…” Her voice caught in her throat. Whatever she was about to say was really affecting her, and I pulled her close. “And… what if this makes it permanent?”

I paused for a moment, unsure how to respond. “Permanent? Diane, for most people their gender is quite the permanent affair. It’s the same for you.” Her eyes widened and she started to look away, so I lifted her chin to look me in the eyes. “But you’re the only one to have ever decided that it wouldn’t be permanent. You created that formula in the basement and became a girl, through and through. So, obviously, you’ll figure out whatever you need to and turn back into a guy when you want to.”

Diane giggled, wiping away some tears and smudging her makeup even more. Her eyelids fluttered at me, and she finally smiled again. I returned it with a smile of my own. “You’re right,” she replied finally. “Besides, I can’t let this get me down now. I have to finish the formula so that we can sell it to everyone who needs it!” Diane planted her lips on my cheek and sprinted off to the basement. I quickly followed her, making sure to keep her round and bouncing ass in sight. Those work tables in the basement are probably at the right height to bend her over on, after all…