Damn, what a good question. This reminds me that I need to write more pussyomi because it’s one of my faveeeee things in this whole wide world.

In general I think that 1) Atsumu really likes to be good at things, 2) he takes a lot of pride in making sure his partner gets off (idk why but I always draw this back to his whole “the points I score are my points, the points my hitters score are my points too” because trust me, atsumu IS keeping track), and 3) his mouth is just made for it lol.

My favorite headcanons tho are just Atsumu ending up a little too fixated on eating pussy. Like he’s just chilling, watching a movie with Kiyoomi, and all it takes is one little rub of Kiyoomi’s legs together, and Atsumu suddenly can’t think of anything else except getting between his legs and drowning himself.

Or Kiyoomi being too tired for sex and Atsumu responding: “but not too tired for this, right?” and he’s perfectly fine just humping the mattress while he eats him out because he truly loves it just that much.