Mud is a main attraction in the sploshing fetish. For many, it is the first substance that introduced them to this fetish, being that mud wrestling has been a prominent novelty of '80's television and movies.
How to not get Bacteria in your ears, eyes, nose, ass, pussy and penis? Well keep away from low tide or the estuaries and even the back yard! All contain harmful Bacteria, just like having sex with dairy products, the will give a lady's private parts a yeast infection quicker than you can say "Cat in the Hat!" Best way to go it to find a Natural Mud Pit like the ones in Texas, here is a sample L attitude and longitude marker, this is not a usable Mud pit, but it will give you an idea of what to search for on Google earth: 30.949186, -97.695910 in fact this is the exact spot where Vixen and I were busted, this site has security guards, even on public holidays DO NOT GO THERE! This type of clay has been irradiated and nothing grows in it, so defiantly no Bacteria there!
The other and I think the best way to go is build your own mud pit. Even the natural clay pits get very cold in winter, you are a better man than I if you can get it up with your balls in cold mud! It will cost you upwards of US$2,000, construction, labor and materials, that's not counting the clay, depending on how big you make it it can be a substantial cost. Mine is 12' x 8' x 4' and 8" it cost me $1,200 for enough clay to fill it. Here is how I built it: http://www.pbhpictures.com/pit.html
A year down the road its still working just fine, I have to cover the clay to stop bugs and leaves getting in and some sort of rain cover is also needed, but you can use all kinds of things to do that. Not only have I shot some fantastic models in this pit but I have also had sex in here more times than I can remember and no issues. I do make some rules, models shower before going in, are not allowed in during their period and of course no body fluids.
I heat mine via solar power and with a decent size collector the pit rarely goes under 70 Deg even in January, in summer it can get up to 90 Deg, so the radiant flooring idea works perfectly, the only issue being the clay does get a bit thick on the bottom.