Green’s Dictionary of Slang

(orig. US) gang rape.

1949		Monteleone Criminal Sl. (rev. edn) 94: gang-banging When teen-age girls are forced by teen-age males to have sexual relations.
1994		N. McCall Makes Me Wanna Holler (1995) 44: I knew what a train was. It was what happened when a bunch of guys got together and jammed the same girl. The white boys called it gang-banging.
2002		(con. 1980s) i80s.com 🌐 gang banging [...] used to describe a group of guys having sex with one girl.