Take a blanket or a rug the next time you roll and start rolling off the edge of the rug. This is a very short decent or assent at first so you will have no problem with it. Fold the rug from time to time and roll off it and back up and learn to relax and let your body take the shape of what you are working with. Do this for a while and than repeat the drill while tensing up and relaxing different body parts.
Soon you will be doing my famous up the stairs roll but let it happen rather than push it. Have fun it is important.