Green’s Dictionary of Slang

a euph. for fuck v. in various senses.

1952		(con. 1920s) implied in forking adj.
1959		D. Niland Big Smoke 169: The nicest little filly I ever forked was a darky.
1972		B. Rodgers Queens’ Vernacular 88: fork (camp: ‘Fork you, Rose, we’re doing it my way!’).
1997–2001		Online Sl. Dict. 🌐 fork 1. a replacement for the offensive term ‘fuck’. Can be used in the same fashion, as in ‘That sucked, I really got forked by them.’.