when a woman is thick and her butt cheeks including muscle and fat and can move them towards and away from each other (kind resembling a clapping motion.)
Sorry I didn't answer the phone, between that bitch moanin' and all the ass clapin' I couldn't hear it!
By Bernardine
Ass-clap
An ass-clap is the proper term for a the following action.
You see your best friend. You proceed to high-five your best friend. As your palms connect, continue on to slap your friend on the ass cheek. Proceed to bask in the awkward awesomeness.