[Zewgor]

In our classes we do floorwork with blankets sometimes, and you make sure your knees are near the edges of the blanket so you have lots of room to move around and not create too much tension, if you can visualize that.  The blanket becomes sort of like a moving and flexible mat and take some of the edge off the knees.  The only drawback is if you're planning on doing shoulder stands or a moves where you need to keep a solid position, since the blanket can make you a little more slippery.  But it's awesome for crawling and kneeling stuff!