Joonmyun thinks his brain turns to mush when Jongin asks if they can bring Sehun in to join them.

“I—huh—wha?” Joonmyun says coherently. Jongin laughs and repeats himself. This causes Joonmyun to stop and think.

It’s not that the idea doesn’t have any merit at all, but Sehun is a baby. He’s Joonmyun’s little roommate and he has to protect him and the idea of corrupting his innocence—

Joonmyun can’t admit it doesn’t have appeal, but he’s not sure he wants to be the one to do it. He’s supposed to be the responsible one. He’s supposed to be the one who holds Sehun’s hand after his innocence has been taken, not the one to take it.

“I’ll think about it,” he says, though his voice wavers when he says it.

That night in their room, his eyes run over Sehun as he changes and he tries to school his look into one less predatory when Sehun turns back to face him. What people would give to see this, he thinks. What people would give to be where he was right then. Sehun isn’t like Jongin, hard muscle and allergy to keeping his shirt on so the whole world can see it with Joonmyun, but Sehun is still sinewy and he has his own helping of hard muscle and for once Joonmyun wants to run his hand over Sehun’s chest, maybe his way down. He mentally curses Jongin for putting this idea into his head.

But he can’t help the curiosity of what it’d be like, and the next day he nods to Jongin, whose smile spreads across his face in glee. “Oh, thank you, Hyung,” he says, and, after checking nobody else is around, presses a quick kiss to Joonmyun’s lips. Their little secret. Their little secret is about to get another witness.

Joonmyun lets Jongin handle it. They’re closer in age, and surely it’d be less weird if Jongin was the one to take control of that situation.

Later that night Sehun stays in their room when Jongin walks in, settles over Joonmyun’s thighs and kisses him hard, leaving him breathless. Sehun stays in their room when Jongin then climbs off Joonmyun, crosses to Sehun, and kisses him lightly, carefully, so as to not spook him.

When Sehun rolls Jongin over and kisses him harder, Joonmyun realises that there is something stronger in Sehun’s movements, something he hasn’t noticed before.

He notices it better when Sehun moves across to kiss him and rub against his thigh and he realises there is no need to corrupt Sehun because someone’s already got there first.