Aoba(you) and Koujaku have been childhood bestfriends but after the two of them managed to stop him from getting posessed and bonded more through the experience you started dating!

Koujaku is a full-time hair dresser and he likes to play with his hair often. It's like his own personal form of affection. Sometimes he'll put strands of Aoba's hair in his mouth, which Aoba finds odd but doesn't question it. It also very much does not help that Aoba's hair is sensitive, like exposed nerves, even if it looks normal (apart from being bright blue) it's still a thing that has to be handled delicately. Which Koujaku always does.

The pair were sitting on the couch, Aoba sitting in his lap while Koujaku braided his hair. It felt nice, just something mundane that kept Koujaku busy while they watched TV and Aoba didn't mind it much as long as Koujaku didn't touch closer to where the strands connected to his scalp.

"Your hair is beautiful, so well kept" he praises though in a way where he doesn't seem to exactly be talking to Aoba, then presses a kiss to the back of his neck.