As you slowly come to your senses, you realise that a bunch of guys about your age are being led into the gym, all of them naked and with hard erections. Something about them seems familiar, and it soon makes sense- while you were getting turned into girls, the girls were getting turned into boys.
You can't focus on what the teacher's saying since you're still in a haze, but fortunately a couple of the guys come up to you and Stevie. One of them pulls her off you, and you see the other, recognising it as Mina, though now he's a boy. He pulls you up carefully, and says kindly, "You look really pretty like this," before pulling you into a kiss.
Almost mindlessly you kiss him back, and as his body presses against you you're reminded again how masculine he's become and how feminine you've become. His firm chest rubs against your soft breasts and erect nipples; his large hands grip your petite ones as his strong arms carefully push you down; and the head of his penis brushes over your clit and down your moistened lips. The message is unmissable: he is male, you are female, and he will mate you.
"I don't think I'm gonna be able to stop," Mina admits just before pushing inside.
"I mean, I couldn't either," you smile. With that, you gasp as his cock head slides between your lips, followed by each and every inch of his shaft. Taking a penis inside you is a bit more intense than you expected, but soon you get used to his size. It helps that he reaches to cup your boobs and rub your nipples while he holds still.
Once Mina can feel you're loose enough, he moves his hips back and pounds back in so firm you feel his balls slap at you, panting with anticipation and making you moan softly. He continues this motion rhythmically, thrusting enthusiastically in and out of you and making you shake with pleasure under him. This feels so good it's making you wonder why you ever liked being a man if getting fucked is like this compared to fucking someone. He thrusts harder and faster, the pleasure mounting and mounting for both of you as you approach orgasm.
At last, with one more rub at your G-spot, Mina groans and you feel him stiffen and his head twitch inside you as he shoots his warm, thick seed inside you, filling you up. The sensation drives you to your own peak, and you clench around his cock, milking him dry.
Slowly the two of you recover from your highs and, panting, lean in to kiss each other.