I can only hook up with girls when I'M drunk?

So a quick recap on my situation. Im a junior in high school and im pretty social and do not have a hard time talking girls. But when I go out to parties it doesnt seem like any (at least some of the girls im looking for) are interested in me. But when i drink at parties it seems like girls want me so much more, and i almost always end up hooking up with a girl. I dont get it? i mean i like drinking but i dont always want to and would like to hook up with girls being sober too.