If my memory is correct, this yaoi school life genre manga has inter-link stories. I think the main protagonist a high schooler was dating his teacher. I read this manga once and only remember the supporting characters. Though I can't recall if they were gay to begin with. Sitting on the roof top of the school, the tall persistent blonde hair guy (seme) advances on an unwilling short classmate with black hair (uke) and later they become lovers. Time skips, the uke had a growth spurt and feels insecure from always being bottom and wants to top the seme. A sensitive topic they would bicker about during intercourse. Entering college, the seme gets approached by a female friend who set her eyes on the uke and unaware of the two guys' intimate relationship. Except, the seme agrees to put in a good word for her since he wants the uke to experience being a TACHI. Yet at the same time, the seme is afraid he might loose the uke to his female friend. In the end the seme becomes the NEKO for the uke. 😐

AnGELs N DeMONs