A knuckles is a person
who is a bad ass often using the catch phrase
H.X.C (Hardcore) or often saying: Yo Yo Yo B Boy That Shits for Real Mutha Fucka’, for Shit, Bitch…Fuckin’ Ass and Blab Blab. Knuckles is also
a sexual move where you shove
your whole fist
into a women's ass and say one or both of the two aforementioned catch phrases.