Just thought I'd share my at-home shower mess setup - please share your ideas as well!
Everything I do is shaving cream based - Barbasol Sensitive Skin only. I usually go through 4-6 cans for one session depending on how much, ahem, chemical alteration I've had.
Beverage Cooler - I fill this with very warm water ahead of time. That way I have a supply of water for mixing, etc. during the session without having to turn the shower on.
Workout Bench - Gets the cooler off the floor so you can use the spigot to fill the mixing bowl, also provides a place to sit when the ol' knees give out.
Silicone Cake Pan - What I fill to make pies. Depending on ratio of water to cream, can be anything from stiff foam to warm slop. It's flexible so it's easier on the face, and you can even launch the "pie" filling at yourself by grabbing the handles and pulling.
Chocolate/Strawberry Syrup - pie topping. I tried poster paint and love the colors but don't like the taste much. This gives you some color while tasting OK.
Mixing Bowl - used to mix up pie filling, fill with slop, dump, push down over head, etc.
Hand mixer - this works really well for turning foam + water into any consistency you want
Big sponge - apparently I'm also into boxing/ko play and this makes a good fake fist, or giant monster tongue, or whatever your perverted imagination wants to make of it. Soak in water, lay on some cream and whack!
Mosquito swatter - Feels amazing to put a big load of foam on it and then smack yourself. Just be careful.
Paint Syringe - Load this up with foam and water and push the handle in a jerky way and well, not too much imagination needed to guess what this represents.
Sound buttons - these are little buttons that you can record your own audio on, and then press the button to trigger that audio. They come in 8 packs for training dogs. I put them in ziploc bags to protect them in the shower. I recorded different crowd laughs, women laughing, sad trombone noises, etc. This was an amazing addition that I haven't seen mentioned here before.
Love you, too
