Stand on your left leg with your right knee and calf supported on a cushioned chair or low sofa. Your weight is supported by your right arm which is placed securely next to your right knee. Bend your left knee a bit, bend your torso forward slightly, and let your left arm dangle from your shoulder. Gently rocking your torso forward and to the left, and backward and to the right, allow your left arm to gently swing in a small counterclockwise circle. You're not using any shoulder muscles - the motion of your torso is causing your arm to move in the circle.