Green’s Dictionary of Slang

(orig. US) intercourse in which the man rubs his penis between the woman’s breasts.

1972		R.A. Wilson Playboy’s Book of Forbidden Words.
1977		L. Heinemann Close Quarters (1987) 191: She would do anything for a fiver — fuck regular, ass-fuck, titty-fuck, lick your asshole.
1993		B. Moore Lex. of Cadet Lang. 152: tit fuck sexual ‘intercourse’ wherein ‘inter’ connotes a ‘course’ between the breasts.
1997–2002		Alt. Eng. Dict. 🌐 titty fuck (noun) masturbation by inserting the penis between smooshed cleavage.
2001		‘Randy Everhard’ Tattoo of a Naked Lady 12: ‘You’d like a tit-fuck, wouldn’t you?’ It wasn’t a question. It was a statement of fact.
2006		T. Dorsey Big Bamboo 136: No cornholing, no tittie-fucks, pearl necklaces, muff diving or golden showers.