Pistoning

piss-ton-ing
(verb)

Rapid back and forth motion contained within the ass (closed first or otherwise) without removing the hand.

(see also: Fisting)

Him: So, how do you like to get fisted?
Me: Pistoning is my favourite! Piston my hole so fast until I cum without jerking off.

bull king

A hyper dominant male, the bull of bulls, who can pound and breed all night.

Bojan is such a bull king, he pounded me for hours!