The way your knuckles look after eating a popcorn from the bag. "usually dark yellow"
i was riding my bike and noticed i had Butter Knuckles
by tophercat9 July 10, 2010
The act of fisting a girl, pulling out the fist to realize there is a butter-like glaze all over your hand
Dude, i was fisting your mom last night, and realized she gave me butterknuckles.
by DPELL06 October 26, 2008