INFP guys (the only kind I personally know) - really wacky dudes....like even wackier than me. Not in a super hyper way, but he'd just have absolutley no filter in terms of what to talk about. He'd shake a girl's hand and tell her he masturbated with that hand for shits and giggles. My Fe was like (What the fuck are you doing? You won't ever have a chance with her again!).
He was pretty cool before we lost contact for little reason. He was pretty cool in that he provided various tools, books for my hobbies and stuff (psychology at the time). I do wish he was still around.
In terms of INFP girls....this isn't experience based, but I'd speculate we'd try to rip one another's throats out due to her Fi.