Foot knuckling
The art of inserting ones toe up whatever orifice, all the way up to the hilt
Shit me mate......he stuck his toe right up to my tonsils - the dirty low down foot knuckling son of a bitch
foot knuckle
The bony protrusion on either side of the ankle.
Oh man, during that slow pitch softball game my foot knuckle got tore up by a low ball!