Mule Swipe

Banging a girl doggy style and then moments before you blow, sticking your dick in her ass, and then punching her in the back of the head, having the shock of the strike make the womans sphink tighten to a very pleasurable pressure guage. This is a tried and true technique that works best when slightly inebriated (blame it on the Sleeman), as to not get you cock cut off the next day.
AKA the Donkey Punch