look up any word, like smh:
The roll under a woman's chin that even slim women have due to performing too much oral sex with a man over the span of time.
I love getting head from Alisha; she has a very comfortable "Ball Shelf" on her.

Damn girl, you really need get that "Ball Shelf" waxed. This blumpkin just isn't as enjoyable as usual; I hope you get backwashed.
by Heelfigger January 05, 2009
The human chin, esp. in reference to fellatio or tea bagging.
Jay Leno has quite a large ball shelf.
by Zevatron December 26, 2006