To face-fuck a guy, a dude sticks his dick in another guy's mouth and fucks his throat until he has a throat-gasm and lets all the cum that isn't swallowed dribble out of the guy's mouth onto the cocksucker's cock which is being jacked off.
My cadet roomie, Matt, loves to hold my head and face-fuck me!
To dismiss someone angrily, similar to "fuck you" or "fuck off", but more to say that they are also wrong about something they just said to you.
It's a Chicago thing, first appearing in a Yelp Chicago talk thread about the southside of the city being less favored than the north, and the racial and other implications of that.
"Bitch, your tanorexic ass is just mad because you are poor and eat ramen and got roaches and shit."
"I'm not poor at all you wrinkly ho. In fact I got a luxary Audi and my daddy owns half the southside, so fuck your face."
A double-dick face-fuck is a sexual activity that three guys can engage in. Two guys face-fuck another dude with their dicks in his mouth at the same time and try to have cumgasms so they can feel each other's cumshots.