Green’s Dictionary of Slang

fag v.5

[fag n.4 (1)]

(US) a derog. term, meaning to engage in or subject another to homosexual practices.

[US]G. Cuomo Among Thieves 216: It was to your benefit that someone like Penney tried to fag you early, as long as you could cut him down. The word got around, and people left you alone.
[US]R. Campbell Alice in La-La Land (1999) 53: The urge to come out of the closet and go fagging only comes on him every so often.

In phrases

fag around (v.)

(US) of a heterosexual man, to play at acting in a ‘homosexual’ manner.

G. Duay Fruit Salad 122: All their free time is spent faggin’ around [HDAS].
[US]Da Bomb Summer Supplement 6: Fag around (v.) {Offensive, derogatory} When two or more heterosexual men joke around like gays. Usually only done by very close friends who know that nothing is really meant by the playing.