Green’s Dictionary of Slang

mouth fuck v.

to fellate.

1978		L. Kramer Faggots 100: [He was] mouth-fucking the impaled acolyte.
2004		‘What’s Your Pleasure’ at BigStorySite.com 🌐 [of two men] With that, I took my hands off his butt and let him mouth fuck me at his own pace.
2004		www.snatchaddict.com 🌐 Watch Angel Long mouthfucked, while she hangs upside down on his neck! These mouth and face fucking movies are ONLY available at Fuck Her Throat.Com!