The slang of choice right now would appear to be to Crack One Off; features a lot in BBC alt-quiz shows. Recently reacquainted with Greaves & Blegvad's Kew. Rhone. album (thanks again, Pip!) after a 25 year hiatus, I can report on a song thereupon entitled Three Tenses Onanism which begins:

Frank sang a song began
Some guy clobbering a gong
And further - J Arthur Rank
Slang for wank - Jack off.

Again we encounter the general contempt in which male masturbation is held, as oppose to female, which is glorified, exalted & encouraged. The male masturbator is an outcast, sad & solitary, reduced to pleasuring himself because can't get laid; he is the compulsive wanker who falls down the stairs and smashes his pyjamas. The female, on the other hand, is at one with the sexual mysteries of her body, communing with the beauteous glories of venereal understanding, she casts her orgasm as a spell of sparkling diamonds. There exists an Australian website (Abby Winters) in which everyday young Australian women openly masturbate before their video cameras; no models, and no fakery. I wonder, does an equivalent site exist where young men do likewise?