wank attack
When suddenly you get horny for no reason and your hands go down your pants and you wank by pure instinct.
His hands started to shake, and then dove down his pants. "Oh shit, I'm having a wank attack!" he wailed.
Wank Attack
The sudden panic experienced when masterbating and suddenly you hear footsteps nearby or a door opening, or some other indication that you aren't alone. Usually preceded by immediate zipping, minimising, muting and concealing of tissues.
Dude, I had a total wank attack yesterday, I coulda sworn I heard someone coming up the stairs but it was just tiddles, stupid cat.