bookshelf speakers on the floor

I spend a lot of the time on the floor (bad back) and read, listen, waste all the good remaining hours of the day like a lazy cat. I tried a pair of speakers on the floor, - before moving to a stand - and noticed that they sounded better than on a stand - to my ears. When I am on the floor, they sound even better. (Yes, there are a number of things wrong with me)

Is it OK for a bookshelf speaker to be on the floor? And if so, should I put something underneath? (Should I try putting it on my stomach? Just kidding!)