I like my roommate's friend, but I am absolutely sure that his friend doesn't like me.
Whenever he comes over, we spend the whole night being flat-out mean to each other, but in a way that's what attracts me to him-his personality.
why dont you switch it up & not trade insults(or whatever it may be) with him. If he still acts mean, then he probably doesn't. If he acts nice, then he may feel the same. You could even ask your friend to do some low key inquiring to see how he feels.
you never went to primary school then. the meaner someone is to you, the more they like you. by this i mean trading stupid insults. not like being racist or beating the crap out of you.
i'd probably just have the room mate be like "dude, my room mate totally wants you. stop teasing her and go bang. when i'm not home that is".