Random
Source Code
Random
A girl who is so skinny, most likely from anorexia, that when she wears a bikini you can see the bones of her pelvis move around in her ass when she walks because she has almost no butt cheeks.
"Danm! Someone tell that knucklebutt bitch to get some meat on her!"
A person who after having anal sex has a swollen and raised butthole resembling a row of knuckles !
Man , my girlfriend fucked me so hard with a strap on i woke up with knucklebutt !