This is a good drill to unwind the body after a long time with armour or heavy gear on or just a lot of standing. Lie on your back and bring the knees to the stomach. bring the feet toward the head and grasp the bottom of the toes with your hands. Now breath in and let the belly push the knees away and rotate the heels around as the body moves from the breath about 20-50 times and than the same for the other direction. This connects the body with the breath and lets the held tension move and the awareness to the breath return.