Lie on left side and prop yourself up on left elbow, keeping it directly beneath shoulder. Place right hand behind head and bend knees, bringing feet off floor and rolling back onto left butt cheek (where your jeans pocket would be). Contract right side of torso and straighten legs while extending both arms out parallel to the ground toward your legs. Balance on that left butt cheek and hold for 30 seconds or your max time. Then switch sides for another 30 seconds. If you need to tone it down a bit, keep your elbow on the ground.