(verb/gerund) The definition should be self-explanatory: something only a male can do. To fuck a face is to repeatedly ram your cock into the mouth of an individual. In most cases, the mouth is a more-than-adequate substitute for the preferred vagina or anus.

Fucking face is a very popular past-time for gay male couples and heterosexual couples. Anyone can suck face, but lesbians cannot truly fuck face for obvious reasons. In their case, the tongue is a more-than-adequate substitute for the depraved penis.

A casual invitation / threat used by an individual that is not afraid of fucking someone up.