A full fecal beard, which is received when motorboating a girl's butt cheeks.
Dude, I gave myself a Dirty Bin Laden when I was motorboating Michelle last night!
by ZEBRA-NINER June 17, 2010
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A full shit beard - casual - osama i.e. with friends

A full shit beard - formal i.e. at a wedding - Bin Laden
Dirty Osama /Dirty Bin Laden debate:

I can't believe he turned up with a dirty osama - this is clearly a dirty Bin Laden occasion. It is my daughters wedding for fucks sake!!!!!
by karnowski snr December 21, 2008
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