thass; the area in which your ass and thigh join as one. there should be definition between the two, a thigh... then your ass, creating a "shelf" if you will. but when you start to gain weight you loose that definition, thus creating the infamous thass.
*cousin to the kankle
Man, what's with her thass? I can't tell where her thighs stop and her ass starts!!!
By Rosene
Thass
That small area on either a male or females body,that is right between one's ass and one's upper thigh,could be the crease or just that area that on some people just blends together.
Oh that hurts, a spider just crawled up my leg and bit me on the thass!