The black slimey stuff on your feet from hockey skates after skating in them.
There's bumsac all over my feet
by John Fergusen August 15, 2007
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the space or skin between your testicals and your anus.
Sheri: wanna know what turns me on?
Bob: what, girl.
Sheri: when guys lick my bumsac
by s34d0g January 18, 2009
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