Green’s Dictionary of Slang

1. the multiple rape of (usu.) a woman.

1941		G. Legman ‘Lang. of Homosexuality’ Appendix VII in Henry Sex Variants.
1972		D. Jenkins Semi-Tough 58: Trying to write a book during the week of the biggest week in my life is probably less fun than being next-to-last on a high school gang-fuck.

2. (US gay) a male homosexual orgy.

1972

B. Rodgers Queens’ Vernacular 148: homosexual orgy [...] gang-fuck.