Begin sitting or standing upright. Place your tongue on the roof of your mouth. Place each pointer finger on your TMJs, the bony bumps just inf front of your ears and under the cheekbone. Open and close your mouth slowly while keeping your tongue on the roof of your mouth, feeling in your fingers for symmetrical movement of the bones.
One side may move more, so limit motion to the range in which both sides move equally. You may use a mirror to help guide your movement.
Make sure to open only as far as is pain-free with your jaw remaining centered during the exercise.