He tells himself it's wrong.

Believes in it, really.

Kei is asleep and his head is on Masaru's shoulder, and the mission starts at night. It always starts at night.

But it's ten in the morning and Gantz brought them to the apartment.

And they're alone.

After some complaints from a roused-from-sleep Kei regarding the hard floor and Masaru jokingly offering his shoulder to lean on, he got stuck in this.

And, God, does he regret it.

His back is against the wall, at least. But Kei is blushing and his lips are parted, and Masaru can see (because he can't tear his eyes away, will never tear his eyes away, won't even if he knows it's the right thing to do—) the way his cheeks lightly dust with pink. When Kei's knuckles brush against the side of his thigh, Masaru takes a deep breath. When Kei starts to rub his temple against Masaru's shoulder and lets out a soft moan, he holds it.

Silence.

His lungs are turning blue.

But now Kei is shifting, turning his head, and Masaru doesn't know how he's still sleeping, but God if it doesn't kill him how his face brushes against his bicep. He shivers and Kei moves his hips up once, and consequences be damned Masaru can't help himself.

He thinks about it. Lets himself think about it. Thinks about that soft noise and the way Kei's hips are circling repeatedly now, the way he's going to slip if he isn't careful—

So Masaru catches him when he does slip off his shoulder. Watches, wide-eyed and flushed, as he gently lowers Kei to his lap and sees the boy start to wiggle and squirm where he lays. His hips are bucking up and he can see it. The line of his cock where it strains against his sweatpants. And Masaru is suddenly so hard all the blood from his brain's seemed to go somewhere else.

His right thigh twitches when Kei turns his head to lie on his side. It seems to be unable to handle being a pillow, too.

His fingers find the left edge of his own length shaped in his pants and Masaru has to bite on his lower lip to hide the sound he wants to make.

This is so fucked up… is the first thing he thinks as he starts to rub himself, tips of his fingers moving over his shaft where it's prominent in his clothing. He watches Kei and hears him pant, his throat going dry. Kei is kissing invisible air and Masaru wants to swoop down and take that tongue in his mouth for himself.

I'm so fucked up… is the second thing he thinks when he slips his hand into his jogging pants and rubs the tip of his dick, a gasp escaping his mouth. Precome beads at the tip and he's tilting his head back, and his chest starts to heave as he takes in rushed sips of air.

Kei moans again and Masaru is biting hard into his inner cheek.

Kei-chan…

He moves his free hand down, down to brush his palm against the bulge in Kei's pants, and the way his friend suddenly whines in his sleep and bucks even more desperately has Masaru leaking.

Kei is grinding against his palm and Masaru's squeezing and rubbing at the head of his cock, and as Kei's moans start to escalate, as Masaru feels wetness against his hand, it's taking all his self-control not to moan out loud, too. He squeezes once and Kei comes and it's hot and staining his pants and Masaru can feel it, but he can't bask because his hand is slipping out of his own pants and Kei is waking up and fuck, fuck, fuck, he came against my hand he came against my hand fuck I want to come too—

Kei's head thumps onto the floor as Masaru gets to his feet and rushes to the bathroom, and he locks the door and jerks himself off until he comes into some tissue, Kei's name on his lips and his heart in his ears.