1 definition by Josh Birchwood

it is a hilarious sexual prank in which you are fucking a girl, and right be fore she finishes you have a tall, skinny friend walk in dressed as slenderman.

Warning: you may get feces and urine on yourself by doing this
To prank my grilfriend, Bob dressed up and pulled The Slenderman in the middle of our alone time. Her reaction was priceless
by Josh Birchwood January 18, 2013
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