Green’s Dictionary of Slang

1. (also french it, french off) to give oral sex; thus Frenching n.

c.1915		implied in Frenching n.
1923		in Poems, Ballads and Parodies 19: Bartender, he Frenched my Nellie, / He kissed it and stole her away.
c.1925		Burgess Papers in K. White First Sexual Revolution (1993) 95: Some of them you cannot tell from a woman [...] They take it in the ass, French you, like to be called girls names.
1949		‘Swasarnt Nerf’ et al. Gay Girl’s Guide 9: french: Another and quasi-straight ephemism for ‘blow’ or do.
1951		D.W. Cory Homosexual in America 105: He Frenches or she likes to French will be said.
1959		‘Count Palmiro Vicarion’ Limericks 28: She admitted men’s poles / At all possible holes, / And she’d bugger, fuck, jerk off, and french.
1965		Guild Dict. Homosexual Terms 17: french (or french it) (v.): To fellate or cunnilingue, the French pretty much being given credit for originating such; usually a heterosexual term.
1970		‘Troy Conway’ Cunning Linguist (1973) 80: ‘I Frenched her, by the devil! I dropped right down between her thighs’.
1972		Milner & Milner Black Players 91: Some [whores] will only ‘flat-back’ or ‘french’.
1979		‘Iceberg Slim’ Airtight Willie and Me 97: The street where [...] for a year, she humped and frenched off myriad multi-ethnic Johns.
1984		C. White Life and Times of Little Richard 23: Madame Oop would french you. He’d suck you.
1989		A. Vachss Hard Candy (1990) 109: You wanna have a party, honey? [...] Ten and two, baby. I french, I do it all.
2001		(con. 1964–8) J. Ellroy Cold Six Thousand 361: I get to geez, you get to watch Ashtray french me.
2011		F. Bill ‘Old Testament Wisdom’ in Crimes in Southern Indiana [ebook] He sounded link a drunk who had Frenched a running chain.

2. to deep kiss.

1955		J.H. O’Hara Ten North Frederick 152: She [...] Frenched me.
1974		G.V. Higgins Cogan’s Trade (1975) 115: The shepherd’s frenching him, for Christ’s sake. Guy finally gets the dog’s tongue out of his mouth.
1981		W. Boyd ‘Hardly Ever’ On the Yankee Station (1982) 49: It got pretty passionate. Frenching just about all the time.
1985		K. Vacha Quiet Fire 146: I kissed him and he started Frenching.
1987		W.T. Vollmann You Bright and Risen Angels (1988) 331: Usually I charge a dollar a kiss and an extra fifty cents for tongue, but you can French me for nothing.
1997–2001		Online Sl. Dict. 🌐 French kiss v 1. to kiss with an open mouth, usually placing one’s tongue in the other person’s mouth. Can also be used as just ‘french.’ (‘They were outside frenching.’).
2000		M.E. Dassad ‘Chickenhawk’ at www.cultdeadcow.com 🌐 I slid up her body as I fucked her [...] and pried her mouth open and began frenching this little slut, thrusting my tongue deep into her mouth.
2005		Mad mag. Mar. 43: He’s frenching me! Help!