Have a spinner with each of the girls names on it. each of The guys spin it and take the girl it lands on. Each girl puts on a blind fold and the timer is started.
First each couple fucks, then the guy uses his art supplies to decorate her pussy. When the time rings, the game is over. Each girl lays still with her lags wide open so the guys can walk around and choose who won. Th winner gets to screw all of the girls at the party how ever he wants.