A shrunken cock or, of that person due to too much alcohol. Aka whiskeydick. Used as an insult or in a self-deprecating way.
A: Hey, what happened to your dick? Seems shriveled.
T: Yeah, I drank too much at the party. Guess I'm having a liquor knob.
V: This man is a knight in shining armor. You should be polishing his lance.
M Excuse me???
A: Your new girlfriend totally rocks!
B: Nah, she's just an entertainmate. Her vag totally rocks tho.