1. A slutty girl with a fat ass. (Noun)
2. A guy who likes easy chicks with a fat ass. (Noun)
3. Jerking off a guy with a huge cock. (verb)
1. My that girl is such a donkey slapper.
2. Dude, stop donkey slapping before you get a disease.
3. Girl, why you go ahead and donkey slap that thing.