So you like to play and have sex in Mud? Unfortunately this is not as easy as it sounds. Yes you can just dig up the back garden, add water and hay instant mud hole, or how about finding tidal Mud flats or and estuary? All are fun and if you are lucky you may find one that is private enough to indulge your fantasies. However if all you want to do is play this types of locations are fine, if you want to go further and have some kind of sex I may warn you against all kinds of bacterial issues that may arise, especially from estuaries or tidal Mud flats. There can also be some sharp or dangerous things just under the surface of the Mud, so be very careful if you try this. Searching Google Earth for stone quarries or concrete processing plants may find you some clay pits, but again beware of what maybe in the Clay, some has been irradiated, some have scary Bacteria in it. There is an inherent danger that you could drown too. Many Mud fetishests like to go under the mud and usually this is not an issue, mud is Very, Very buyent and its almost impossible to sink, but some clay pits have muddy water and in these ponds that can be 50' deep, it is possible to drown. Another possibility is of a legal nature! Most of these Quarry Mud Pits are on private land and its relitvily easy to get caught, I know Rob was caught several times, I have have been caught once and I know one guy who was prosecuted. Had I not been with a large breasted hottie I may have been prosecuted too.
The safest way is to have your very own Mud Bath, but even then there are issues that may stop play! Not everyone has the space, or if you have a spare room in the house use a large kiddie pool and go buy a dozen 50lb bags of clay from the local art supply store. The problem here is heat! Cold mud is not very sexy, so how do you heat it? I am a decent engineer and after 30 years of trying stuff there are very few ways to heat large quantities of clay. Radiant heat is probably the only method that actually works and you can't use that in a plastic kiddie pool.