look up any word, like blumpkin:
 
1.
When you smack someones butt .

A donkey is also refered to as an ass .
So if your smacking the donkey your smacking the ass .
Two guys are talking .

GUY 1: Yeah dudee I was with her last night.
GUY 2: You were totally smacking the donkey weren't you?
by ThatCoolKid. December 25, 2010