Here is inexpensive and flexible solution. Go to any camping store and buy a cheap, basic sleeping pad like this one:
www.rei.com/product/848717/standard-blue-foam-pad-regularMake sure you get a "closed cell foam" type. These do not have to be inflated. it is like a thick, hard sponge that has a little give when compressed, but doesn't squish flat. Try to get the thickest you can: 3/4" or so. They come in different thicknesses. They are easy to cut with scissors. If you want to go deluxe you can get a higher quality closed cell foam from a foam specialty store.
Cut a few layers into either a doughnut or horseshoe shape. you can trim to fit so it is just right for your particular butt. When done, wrap the layers together with some duct tape and then (for appearance) wrap it in some nice cloth or towel. It will last a long time and you can get the shape and thickness just right.
Post Edited (proscapt) : 3/6/2014 10:42:38 PM (GMT-7)