Deucetop
The point of one's butt where the curvature angle is such that there is no greater peak level of elevation; the highest point of one's butt; the arch of the butt
(1) "Yo I climbed that deucetop like a warrior with a battle ax"; (2) "You know I maintain my deucetop like a Cadillac, that shit glistens"; (3) "Wife maintains that deucetop pristine, shit belongs in a gallery"