A.k.a. "going commando", sporting an unfinished basement implies wearing no under garments.
Go pants Todd, he's got an unfinished basement.
by liquidcrack January 21, 2003
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.
by JotaBug June 27, 2009