A poopydoo is when you are engaging in a 69 position with your girlfriend and she farts. Causing you hair to blow back like you stuck your head out of a moving car.
Hey man i was doing the 69 with my girlfriend and she farted so hard my hair blew back, giving me a poopy doo.
A game played by smearing feces onto one side of a dollar bill then placing it poopy side down in a heavily trafficked area. You hilariously watch as people get poopy all on they hands. The game is won when someone keeps the dollar.
That game of poopy dollar was amazing, I can't believe that old lady put it in her purse.