windmill slap 

throwing your arm up in a counterclockwise motion, over your head and back down again (making an invisible circle with your hand), striking the ass of your lover on the upstroke while doing it doggy style

Then I gave her a windmill slap, like I'm Peter Townshend.

windmill slap by IceWater With Lemon January 5, 2009

Windmill Dick Slap

When you propel your man meat in a circular motion mimicking that of a helicopter or a windmill. When inertia has reached its apex one may exert their cosmic dong clock onto un-expecting objects and/or bystanders. Perfected by Willy Nelson in the late 1980's, this of course inspiring his hit single "whip that sausage right round."

Slappee: Why does my head hurt?

Slapper: Well my good sir, due to the omega Windmill Dick Slap I had bestowed onto your forehead, you had slipped into a coma for 27 years 36 days only to be awoken by yet another Windmill Dick Slap to your forehead. And that my friend is why your head hurts.

Windmill Dick Slap by iHateTheUmbrellas June 22, 2011