The act of inserting multiple fingers at least second knuckle deep into your partners rectum, optimally by surprise. Often done during fellatio or cunnilingus.
Sabrina is great at knucklebutting, she can get third knuckle deep before you evennotice.
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 somemeat on her!"
It is said of the situation where a person has the bad luck to make contact with his testicles against an undefined surface or object, intentioned or not.
Given the nature of the word, it is more appropriate to design cases where the interaction is made with a moving object, for example, a ball.
Although it is extremely painful for the victim, it tends to be considerably funny to people who witness it.
Today in the baseball game the pitcher took a nutshot; the baseball hit him in the nuts.
Man, I just watched the funniest nutshot video ever.
A "human" that spends so much time playing video games that their posture is level nerd neck. Everytime anyone goes tryhard they hunch down and their neck gets longer there fore a nerd neck is always hunched down cause they're always going try hard. In other words a nerd neck is a try hard, since their neck is 100% longer than the average human being due to playing too many video games and taking them serious, nerd necks are not even considered human anymore but something more sad. Nerd necks are often found on fortnite, their natural habitat usually being tilted towers.