Green’s Dictionary of Slang

1. cunnilingus.

1899

Horn Book 142: Face Fucking. .. The man’s face is thus between the woman’s thighs and he gamahuches her with the most voluptuous play of his tongue.

2. fellatio in which one partner lies on their back with an opened mouth.

c.1972		‘H. Smith’ 3 Way - Only Way 158: Pete would work on the knob for a few seconds and then invite another face fucking by opening his mouth and trying to swallow the cock [Simes:DLSS].
1980		Beach Boy 49: [I]t was turning into a face fucking. He moved his hand behind the man’s black hair, and held the back of his head. Then, he started to ram his cock in and out of the man’s mouth [Simes:DLSS].
1998		J. Gordon Hard Rider 109: His face was sore from the force of the face-fucking [Simes:DLSS].
2002		an1662 ‘First Time’ on Nifty Erotic Stories Archive 🌐 The guy doing the face fucking, wasn’t my brother, he had black hair, brother was blond, the guy was pumping away and the banging was the head on the headboard.