First off, he announces the next lesson will be segregated by sex. All the girls are sent off to another gym hall, and he writes on the board, 'Male Homosexual Sex'.
You swallow hard, pretty sure you can guess what the consequences of you cumming inside Mina are.
"OK, everyone who didn't cum inside their partner, please come up and take a bottle of lubricant," the teacher says. You stay put, now basically certain what's gonna happen. He instructs those boys to choose a partner, and you see Steve, an admittedly handsome-looking slim guy, come up to you.
"Right, now the people who DID cum inside," the teacher smiles, "and present your anus to your partner. You're going to be bottoming- in other words, the other boy will be fucking you."
Blushing, you get on your hands and knees and let Steve get behind you. He pops open the bottle of lube, and you feel a chill on your tight hole as he rubs the gel-like substance around on it. "Your ass is nice, but you've got a pretty tight ass," he teases.
"Shut up," you hiss embarrassedly.
"Like PIV sex, there are multiple positions you can try. The easiest ones are missionary, which works pretty much the same as with PIV sex, and doggystyle, where the bottom goes on all fours and the top fucks them from behind."
Steve smirks, "Guessing from your position, you wanna do doggystyle?" You don't answer, but something strange happens to you as his cock head rubs along your backdoor and his firm hands grab your torso- it feels pleasurable. Your flaccid cock is starting to get hard again, and when his head pushes inside you, you groan with excitement.
You both start off slow, your butt feeling slightly sore from the insertion and his hips too shaky to thrust properly. But soon he does start thrusting, and once he does, completely contrary to your expectations you're in heaven.
You've never been filled like this before, but it feels amazingly satisfying. His firm hips and thighs and hands against you feel so warm and enticing, to say nothing of the weird feeling of his balls slapping against you with each thrust. At times he even slaps your ass, and reaches down to rub your cock, and you moan at how sensitive it feels to have it rubbed while being fucked.
But what feels best of all is when his cock starts rubbing your prostate after several thrusts. As soon as he hits that spot, you feel like you're gonna peak. And after a few thrusts, you do, cumming messily over the gym mat under you.
As you cum, your ass clenches around him and he groans as he cums inside you, his warm seed filling your tight hole and starting to leak out of you. You feel his cum running down your perineum and balls as he twitches inside you.
When he pulls out, the thrill of orgasm is fading, and you feel really confused. You just got to cum inside a girl, and then a guy fucked you and you enjoyed it despite always assuming you were straight. And yet somehow, you have a feeling this lesson will only get weirder...