So, at a party the other weekend, there was this sexy chick dancing. I go to an engineering school (premed, not an engineering major) so the male competition is rarely tough at parties around my campus. The friend who invited me is cool and women love him, but he's gay, so no probs.

Anyway, I start dancing and talking to this girl super close. Eventually, she's getting pretty drunk and blows me in my friend's bedroom. An hour or so later, she starts complaining because she's "allergic to vodka and beer." She drank both.

She has a friend call her boyfriend, but then complains that she doesn't want him to come over. Since he's on his way, he still comes over, but she is like a fucking wreck when he makes it there. Much to my chagrin, it is a friend of mine. Not exactly a close friend, but someone that I see once a month or so. He's very much in my social circle. He's an attractive guy, but is too agreeable. Even while he was over, the three of us were sitting on the couch and she would crawl into my lap to grind her pussy on my thigh. I didn't stop her and neither did he.

Question: Should I warn him about this girl in some way? My initial thought is that it's not my responsibility. I also expect that she has no interest in telling him, but don't trust her even a little. Dude is yoked and taller than me, but very chill. Any thoughts on best procedure for these kinds of situations?