The primary reason for differing mattress toppers is the position a person sleeps. Therefore, if you sleep on your side, you’ll appreciate a medium firmness that offers enough support to prevent pressure point pain and is soft enough to relax your body gently. For back sleepers, a firmer mattress may be preferred to help prevent your body from slipping into an awkward position. Though some of this depends on personal preference and body type, you can think of a mattress topper for side sleepers to be Goldilocks’ pick from the fairy tale, Goldilocks and the Three Bears: Not too hard, not too soft, but just right.