oopie-poopie
A game largely played by suburban youths which includes several young boys or girls standing in a circle. When the whistle is blown indicating that the game has begun, each person defecates on the ground. The person who defecates the smallest is then obligated to roll around in everyone elses feces while the rest of the group screams "OOPIE-POOPIE!!!"
That was really a sloppy game of OOPIE-POOPIE we played last weekend after eating at taco bell; I really feel bad for dan.