How Do You Get In Her Pants On The First Date ?

Clearly it's possible, but does the circumstance and/or mood already have to be aligned to make the feelings/desires/reactions conducive to erotic signalling from one person to the other? Who makes the first moves?

ie. does the girl take the guys hand and put it in her pants, or does the girl put her hand into his? If it's two girls (or two guys) how does it work?