Start here for a gentle sequence that activates the core while releasing the lower back.
The hammock is used to support the lower legs, providing a "weightlessness" to the pelvis, and the side to side waving action releases tension throughout the entire body.
You may want to use a prop to space out your lower legs if you feel they are being drawn uncomfortably together. If so, a rolled up yoga mat, blanket, or a yoga block will all work nicely. If your head feels strained resting on the floor, use a pillow for support.