the idea is simple. you will need a zip strip and a can of Febreze. when your ready for the "attack" simply pull the strip tight and their you go.
now it's your turn to have fun. paint the can, get some actors, you could even set it up so it sprays through the wall.
so next time your painting a smile on your face, remember the little details that give the audience a grin (weather they want it or not).