I was thinking back today about a friend of mine who once had a bath problem. She like many was renting and the bath tub was less than stellar. I then was reminded of all the period movies I love to watch and how many times in the Victorian days or earlier people didn't take baths completely naked. Hard to believe that to cleanse your body you had to stay dressed, but when you think about no central heat, those with the privilege of a private bath tub having servants, and other such concerns it makes sense.
So my suggestion to my friend lay down a towel or old sheet (twin works best) to lay on in the tub. When you are done ring it out and hang it to dry in your tub. If you want to get really fancy you could create yourself a bathing robe (think long lightweight cotton nightgown). My thought is not only will it keep you from feeling icky putting your bare bum on the tub, but also use the fabric as an all over washcloth.
Just some ideas from someone who has to clean the bath tub before every bath (just a little bit obsessive compulsive). I used to keep a wash cloth to sit on when I had an old tub with the stick on no skid stickers, they used to creep me out.
Well just one of my ramblings while driving home.
Draining the tub,