A parlor trick played on one of your unsuspecting friends (or strangers.) When someone is bending over to pick up something, you put your hands together flat to make a shark fin. Then you shove it in their asscrack and yell 'SHARK IN THE BUNS!'

Hilarity ensues. Bonds are made and broken.
'Hey, I dropped my pen can you pick it up for me?... SHARK IN THE BUNS!!'
by The Big LeChowski October 25, 2006
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