Sir Charles
A female's large behind.
There are several levels of Sir Charles.
Level 1: A Normal Sir Charles - Just a great big ass
Level 2: A '93 NBA Finals Sir Charles - An incredibly shapely, gigantic ass
Level 3: A '92 Dream Team Sir Charles - The greatest ass of all-time

Derived from Charles Barkley's nickname "The Round Mound of Rebound," except in this case it's the "Round Mound You Wanna Take to Pound Town"
Kim Kardashian has a '92 Dream Team Sir Charles