give everyone at the party a balloon. holes in the one it's not so only the right balloons blow up? Or take pictures where mom and dad both have balloons ready to blow up. Next photo the right color balloon is blown up.
I'm only pinning this because I'm appalled by the horrible grammatical error at the end that has eluded countless pinners before me. "Change the filling in just ONE cupcake - reveal will take place when that particular cupcake gets ate.