As most of us know, and often through disastrous trial-and-error, mixing flour and water can make a fun-looking batter or thick liquid that is tempting to get messy with. But as most of us know by now, the gluten in the flour will seek out body hairs and hang onto them. Clean-up becomes torture. There are two rather inexpensive and easy solutions to this. It is to add a liberal amount of either detergent or oil to the four and water. Detergent should be something body-safe, such as baby shampoo, and oil may be cooking oil or baby oil. The amount of the added liquid is crucial to prevent the flour mix from sticking to body hairs. At least a third of the liquid ought to be detergent or oil, with the other 2 thirds water. To play it even safer, you could go with a 50/50 mixture of water to oil or detergent. You'll still need to mix the hell out of the flour with the liquid mixture added. (and pre-mixed) Clean-up is easier if you use something like shampoo. Do NOT let any of the mixture harden on a tub, wading pool, clothes, etc. as it will become rock-hard fairly quickly. The best thing is to enjoy the mess, then immediately rinse it down the drain with plenty of water. If the batter is thick, you'll want to get out, then mix in water so you wind up with a thin solution going down the drain, rather than any thick stuff that could easily clog the pipes. Most people avoid flour due to the hair-pulling balls of flour that are so hard to get rid of afterwards. This method works, but try it at your own risk, and make a small batch to experiment with the quantities before committing to filling a tub or pool. Another option would be to use non-gluten flour, but I believe it is much more expensive and comes in very small packages.