1 definition by KinkyCactus

bum lips

The rim of your anus typically with a circumference 2πr, r being the radius of the ass pussy. This has an exponential growth whether you are excreting waste, or receiving sweet love which is proportionate to each persons bum cheek volume.

Jonathan dropped the soap and felt the exponential growth of his bum lips

by KinkyCactus April 22, 2016