Summarize this article:

Do each of the following for 5-10 seconds as you get ready for bed:  Touch your tongue to the roof of your mouth, then open your mouth as wide as you can without pain. Keep your tongue against the roof of your mouth, then slide your lower jaw as far out as you can. After that, slide it in as far as you can. Open your mouth as wide as you comfortably can, with your tongue in a neutral position. Then, close your mouth and reopen it slightly, slide your jaw to the left for 5-10 seconds, then slide it to the right for 5-10 seconds. Clamp a pencil, paintbrush, or similar object between your front teeth, securely but not forcefully. Slowly glide your lower jaw forward as far as you comfortably can, without letting the object fall out of your mouth. Hold the position for 20 seconds.  Try doing this 2-3 times nightly before bedtime. Over time, you may be able to do this exercise with a thicker object, like a child’s easy-grip pencil. Hold your thumb firmly against the underside of your chin. Press your thumb up with moderate force and open your mouth until it is comfortably wide, against the resistance of your thumb. Hold the position for 5-10 seconds.  The resistance provided by your thumb makes this a jaw strengthening exercise. Try doing this exercise 2-3 times each morning. Touch your index finger between your lower lip and your chin, then open your mouth comfortably wide. Press your finger against the front of your jaw with moderate force, and slowly close your mouth against this resistance.  This strengthening exercise targets different areas of your jaw muscles than the thumb exercise. Repeat this exercise 2-3 times each morning.

Summary:
Repeat a series of 3 simple jaw stretches every evening. Add a jaw stretch using a pencil to your nightly routine. Press your thumb to your chin as a wake-up exercise. Follow up with a second jaw exercise using your index finger each morning.