The labia of a promiscuous woman. Can also be used to generally describe skanky, undesirable pussy-lips.
"Man, I went out with this girl last night, and she had a pair of bastard flaps on her."
"I hate it when a girl forgets to clean her bastard flaps"
"I hate it when a girl forgets to clean her bastard flaps"
by smokythebandit June 2, 2014