look up any word, like fellated:
 
1.
When you're doing a girl extremely hard from behind, and very randomly, usually during climax, you slap her very hard on the ass so hard that it hurts and when she looks back to see what the fuck you put one finger over your mouth and go "Shhh just shhhh"
Susie got McFattled by Johnny tuesday.
by Mr. McFattle August 11, 2008