Start this exercise by lying flat on your back with knees at a 45 - degree angle and feet planted on the mattress. (holtorfmed.com)
Now, this implementation is no good if the phone is lying flat on its back on a desk. (t3.com)
Start by lying flat on your back then bring one leg across your body, slowly rotating your gaze and upper body in the opposite direction. (lifehack.org)