It's when a woman takes anal beads, shoves it up the man's ass, and proceeds to twist them around in a "door-knob-esque" fashion.
She then removes the anal beads from his ass, and smacks him repeatedly in the face with the dirty beads.
Hence, we have a dirty doorknob.
"I dirty doorknobbed that faggot good!"
Buy a
Dirty Doorknob
mug!
