Supine Spinal Twist

Lie flat on your back with your arms out to the sides at shoulder height, palms down. Bend both knees up toward your chest, then let them fall together to one side while keeping both shoulders pressed into the floor. Your lower back and hips do the rotating while your upper back stays anchored, which is what actually stretches your spine rather than just tipping your whole body over. Keep your knees stacked one on top of the other instead of letting the top one slide forward. Breathe into your lower back as the weight of your legs pulls the stretch a little deeper, then bring your knees back to center and let them fall to the other side.