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Meaning that you can see someone's butt crack or underwear slightly as a person is bending over similar to the zipper of a backpack being slightly open.
(Emily bends down to grab books) Me: Hey Emily you've got an open backpack
Emily: Did you notice my new Victoria's Secret thong?
Me: No I was just looking at your crack.
Emily: You're an asshole.
Me: LOL get it?
by mastablasta5000 October 20, 2011
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