Green’s Dictionary of Slang

chuff v.1

1. a euph. synon. for fuck v., in lit. and fig. senses, mainly used in the north of England.

[UK]W. Hall Long and the Short and the Tall Act I: I’m going to grab a weekend off, and chuff the expense.
[UK]P. Tinniswood Touch of Daniel 12: ‘I just missed one bus, and I thought: “Chuff me, I’m not waiting for another.”’ [Simes:DLSS].
[Aus](con. 1941) R. Beilby Gunner 139: It’s just that the old bloke’s sick so it might be better if you chuffed off.

2. to masturbate.

[UK]Farmer & Henley Sl. & Its Analogues III 74/1: frig, verb. English synonyms: to chuff .

In compounds

chuff-box (n.) [box n.1 (1) or dial. chuff, to cuff, to hit. The penis ‘hits’ the vagina during intercourse]

the vagina.

[US]Trimble 5000 Adult Sex Words and Phrases.
[US]Maledicta IV:2 (Winter) 193: The grocery, the butcher’s and the sweet shop are all represented as well as the greengrocer’s. Thus there is […] banger (a sausage, so-called because it spits when put in the oven = chuff-box).