The act of reverse mounting a person's mouth with one's genitalia to give a temporary pubic hair beard. The pubic hair acts as a beard "dickie", if you will. The mountee can be male, but a chinwig is usually applied by a male to a female.
Dude...I totally gave your mom a chinwig last night.
1. An almost imperceptibly fake goatee.
2. A head wig used as a beard.
"Jim, I like that chinwig on you. Brings out your eyes."
"Huh? What chinwig?" *nervous*