Donkey Knocking 

While riding your pertner from behind, just before shooting your load, hit her round the head with something hard. This causes her to contract giving the beholder great pleasure

Last night i donkey knocked my girlfriend, today i am a new man!

Donkey Knocking by Minchos May 2, 2003

knocking out the donkey

to fuck a girl in the ass, and right as you're about to cum, you punch her in the back of the head so she tenses up.

The best orgasm I ever had was knocking out the donkey.

knocking out the donkey by Deez Nutz May 30, 2004