A/N: Holy God, I am such an angst machine when it comes to these two. It's starting to make me sad. I want to write happy future fic about them when they've both happily gone their separate ways with their respective spouses and live together in a house in the country or something.
Disclaimer: Bakuman belongs to Ohba and Obata, who are bastards but I love them anyway.
Mashiro's not sure when this happened—when going to the studio late at night to do some extra work stopped being true, when he stopped wanting to be around Miho, when he started using work almost solely as an excuse to see Shujin without their wives around.
He remembers the first time they kissed—well, the second time; the first time happened when they were sixteen, and it was sort of but not really an accident, a brush of lips in their excitement at some piece of good news they'd received from Hattori-san—Shujin leaning over his shoulder to look at something he'd drawn, a character design, maybe? And Mashiro had turned his head, and before Mashiro knew it Shujin had him bent over the back of the couch and his tongue shoved inside him, and God it had felt better, more right, than anything he'd ever done with Miho.
Perhaps that was the start, or perhaps it was the first time they really made love, or perhaps it was when he realized that he far, far preferred his time with Shujin to being with Miho. How stupid he'd been to ask a girl to marry him when he was fifteen and actually follow through with it when he'd seen her only a handful of times before their wedding…
He wonders vaguely if they'll get caught someday, even hopes a bit, as Shujin pushes him onto his back on his drawing table—he's laying on a couple finished pages for the new chapter and right now he can't even bring himself to care—and yanks open the drawer containing the lube and a condom. It's not as if Miho and Kaya don't both have keys to the place. If they walked in to see this—Mashiro can't imagine another way life could get a thousand times better and a thousand times worse at once.
Shujin takes about thirty seconds preparing him, but that's all Mashiro needs, really—he's used to not having much preparation, and Shujin likes it rough.
The feeling of Shujin inside him is one that is both familiar to him and eternally surprising. It surprises him that he never, ever gets tired of it, even the ache at the beginning, the uncomfortable feeling of being stretched, until his body gives, relaxes, and all he can feel is pleasure as Shujin's cock slides fast and hard in and out of him, striking his prostate, as a hand on his erection strokes in time with the thrusts, as Shujin looks at him with a wantin his eyes that is so heartbreakingly wistful Mashiro isn't sure whether he wants to cry or come more.
Coming wins in the end, and instead of crying when Shujin collapses on him, still bent over the desk, breathing hard and hot against his neck, he cradles Shujin's head in his hands, tight like he's clinging to a lifeline but gentle like he's afraid this scene will shatter—it will, inevitably—and whispers, "I love you," even though it won't change anything.