Setup and Key Actions
Begin lying on your back with your knees bent, feet flat on the floor, and arms extended out like a letter "T" (or bent like goalposts if you don't have room). Press your feet into the floor, pick up your hips, and shift them to the right. On an exhale, lower your knees over to the left. Keep the backs of both shoulder blades on the floor. Either keep your head centered, or turn your head (not just your chin) in the opposite direction of your knees. Lengthen your spine, and twist your belly away from your knees (as though pointing your navel up toward the ceiling). Broaden your collarbones (especially on the side that you're twisting away from) and settle the heads of your arm bones back into the shoulder sockets. Lengthen your spine a little more with every inhale, and with every exhale, find a little more twist. Keep the twist in your middle back (not your lower back). You can practice with both knees bent, or extend your bottom leg long.
Practice with a bolster between your knees for a more gentle variation. If the shoulder of the side you're twisting away from is lifted away from the floor, bend your elbow, keep your elbow on the floor, and bring your hand to rest on your rib cage. Avoid practicing with the arm extended and the shoulder lifted, which may cause injury to the shoulder over time.