1. and gang-shag n. an act of serial copulation, with one female and a group of males. It was nothing but a gang-bang, and a drunken one at that.
2. and gang-shag n. group rape of a woman. There was another gang-bang in the park last week.
3. in. & in. to perform an act of serial copulation, as in senses 1 or 2. A bunch of guys gang-banged Sally, for a fee, of course.
4. tv. & in. to gang up on someone or something. They’re always gang-banging. The punks!