How is this shounen ai? （￣へ￣）

it's bait

mano and carbel kiss sort of, more like bite the lips but even more so is all the sexual tension between mano and carbel.

that's why

Some Shounen-Ai manga are labeled as Shoujo since dating isn't really involved. Maybe that's the case here. We all know they're gonna have feelings for each other (hopefully) but nothing's gonna happen (probably).

aka bait