Unfinished basement
The not-completely-wiped asshole or the act of tossing the salad of someone with said asshole.
Phyllis nearly threw up when she licked Chris' asshole and discovered that he had an unfinished basement. She promptly bought him an extra roll of TP.
Unfinished Basement
A.k.a. "going commando", sporting an unfinished basement implies wearing no under garments.
Go pants Todd, he's got an unfinished basement.
unfinished basement light
Unfinished basement light is used on things that don't do their job properly. The basement is dark and the light doesn't work to light it up. Also used in places where a construction worker decides to quit and handed his coworker a sock and said "the basement light is unfinished".
Lisa, you are an unfinished basement light to this project.