When it finally happened, Shikamaru was unsurprised.
He made a habit of being observant, and he'd been aware of a shift in Chouji's demeanor toward him for awhile. He'd thought about it quite a lot himself--he couldn't say he didn't also feel the pull of something greater than friendship between them--but there were other considerations that had so far kept him from doing anything about it.
"This is against the rules, y'know," he said, when Chouji pulled back from kissing him.
"Yeah." Chouji's expression crumpled a little in obvious disappointment, and Shikamaru could have kicked himself for letting that be the first thing out of his mouth. Especially when those rules forbidding intra-team fraternization were almost never enforced these days and Team 10 hadn't exactly been an official team ever since Asuma died anyway. They functioned as a squad more often than not, because they worked well together, but all of them frequently ran missions in other team formations too.
None of which was anything he actually needed to be thinking about right now, not when Chouji looked ready to duck out and find someplace other than here to be. Sighing, Shikamaru shushed the constant voice of logic and analysis in the back of his head for just a moment and slid his arms close around Chouji's neck, tilted in and kissed his best friend with all the feelings that he technically wasn't supposed to be allowed to feel, because Chouji deserved at least that much.
"...Breaking the rules is troublesome, isn't it?" Chouji asked tentatively, when Shikamaru drew back.
Shikamaru quirked up one corner of his mouth. "Definitely. But maybe that just means it's worth it."
Chouji's answering grin was enough to convince him of the truth in his own words.