Drink lots of water and if playing down there careful for uti
My wife and a friend w benefits have gotten
UTIs from minimal amounts of stuff in there. Some people go all in and fill her up and don't seem to have any problems. Also any milk based stuff will leave a smell. If playing in clothes or on bed def will need to wash sheets and maybe smell might get stuck. If a lot of playing on head maybe ear plugs so no ear infections
Don't use foods you or he are Allergic or have food sensitivities too, or anyone sharing tub/ shower. The steam mixed with stuff in hug amounts can be bad if breathed in a lot