He is just a red flag dude. Ugh! Why that badass girl sleep with this asshole i want him to fall harder for her.
I mean they're apparently not in a relationship. If he doesn't have any feelings for her then it can't be helped, but if he leads her on even while knowing her true feelings then he'd really be an asshole. ╮(￣▽￣)╭
I'd rather she find a person who truly appreciates her than be with someone who doesn't. If he comes to like her then fine else she should break off from him given the chance.
The sunbae being such a teaser was a telltale sign that he was indeed a sadist. I usually don't like scenes with the side character's 'private life' but this one doesn't really bother me. I guess because he seems like an idiot who's interested in sex rather than one with malicious intent.