I once surprised my wife with an inflatable pool filled with liquid clay (the type used to pour into molds for basic ceramic items) set up in our bedroom when she got home from work. She played around in the pool for a while as I watched but it did NOT take long for me to join her or for both of us to give in to how incredibly turned on we were! (Sadly, she doesn't look too thrilled in the one attached photo but, believe me, she was!!!) Anyway, to answer your question (well, half of your question since I have not been green-lighted for anal), we enjoyed some incredible muddy sex and she showed no ill-effects afterwards. She *did* retreat to the shower fairly quickly after the act and was quite thorough in her clean-up but I think that as long as your "mud" is 100% "clean" clay, you should be all set to get it inside you. Regarding the dust situation, I think that if you wear a mask while mixing, you should be fine. You are going to get fine particulate settling in the room no matter how hard you try to minimize the mess so, sadly, you may have to accept the fact that you are going to be doing some dusting! This sounds pretty exciting though... I'm excited for you. Happy sploshing!
(And I certainly hope you post some pics if not video of the event here!)
"Natural" ball clay is very inert & mostly bacteria free so the chances of any ill effects would be small Breathing in the dust is another matter & I would say a mask is a minimum precaution
A dust mask is a good idea. I would mix it in the bathroom or smallest room you have and then just wipe up the dust after. A vacuum will just get plugged up and may get into the motor. Mix the clay slowly so as to create as little dust as possible. I like to use Red Art ball clay and mix it with C&C Ball clay. Yes it is very sensual. 100% Red Art looks like deep red chocolate and is heavy feeling. Especially when very thick with full coverage. For me, the thicker the better. ~mudfinflyer