On the bus ride to school, you're feeling kinda anxious, like you've got a big test coming up or something. But in reality, of course, you're having the change today. Your year were getting a 'reversal' change- all the boys would be turned into girls, and all the girls into boys. Despite your friend Martin, who had spent some of last year as Mariann, reassuring you that it was actually pretty cool, you still felt really nervous about it. After you'd jacked off yesterday to calm yourself down, you barely managed to get any sleep, too worried about how starting tomorrow you wouldn't have a cock and you'd have breasts and... fuck, it all scared you a lot!
Once you got there, you stood in the queue for the boys to become girls, trying to summon up your courage as you waited for what felt like hours. Eventually, you were called forward, and stepped into the room. A sign lit up on the monitor in front of you telling you 'Please take off your clothes.' Shakily, you did so, placing them on the floor and sitting on an illuminated chair in the room's middle.
Stirrups sealed around your ankles, and a slight prick in your arm alerted you to the injection of the hormones which triggered the changes. To your surprise, unlike most injections where after the prick you basically feel nothing or a little numbness, the hormones rapidly made you feel really nice. You started to get hard, and a tube moved to encircle your cock. Your hips softly pumped towards it and you rapidly reached your peak. Soon you shot what felt like an entire lifetime of seed into the tube, and it didn't let a single drop leak out.
As you came down from the high of the tube masturbating you, you noticed how your body had started to change. Your muscles seemed more lithe and like they had shrunk. Your figure had shifted, your shoulders narrower and your hips wider. Your butt seemed larger and your skin softer, and your body hair had practically vanished. Now you'd cum, and released a massive amount of masculine hormones, the feminizing hormones were setting to work on your sex characteristics.
This quickly made itself known in two ways. Your nipples surged with sensitiveness, their erect state suddenly much more pleasurable to you, and your balls moved up inside you, creating a sense of emptiness your new hormones informed you was not because of your emasculation. Guided by the hormones, your body adjusted itself to accommodate the hormones. Your chest swelled, flatness being replaced by soft breasts around your sensitive nipples, and in the space where your balls had been, a vaginal passage and womb formed inside you as your former testicles shifted into place to form ovaries.
Through all of this, your erection had dulled and your penis had settled into place above your slowly-forming vagina. It continued to recede until finally it formed a tiny hooded nub at your crotch, just as sensitive if not moreso. You had a clit now.
Finally you felt the pressure at your crotch relieve as your former scrotum opened into a set of vaginal lips, moisture accumulating from your arousal. By now your body had adapted to produce the hormones you'd been injected with, and you felt no uncertainty about yourself despite how dramatically you'd changed.
It felt kinda wonderful, actually. You'd been scared to become a girl, but you'd gone through with it and it felt so nice.