User story645, you're right.
Both are ass. One is kind of a stalker that temps in and other one is desperate. Betting Ayane is like that (suddenly going 180 from her usual self during heat) because of family (maybe school too) issue which so far there's 0 mention + attempted rape that makes her gives in in desperation. I mean, just look at how sad and tired she is in those panels before. She's probably unconsciously trying to get her negative feelings out by doing it.
sighhhh... But still, my initial expectation for this manga is totally gone now. I really shouldn't easily expect that kind of story from ABO setting.