Apart it fro being a Tibetan Custom for showing respect, sticking out your tongue can be therapeutic. 
The tongue strongly influences the jaw. Try opening your mouth fully with your tongue pulled back toward your throat. Then try opening your mouth with your tongue moving forward and downward like our tiger in the picture. You will find it a lot easier with the later method.
In North American culture your tongue should not be seen. It is associated with disrespect, laziness, and stupidity. When tense, we hold it back or press it to the roof of the mouth. All this has functional effects. Normally it should be resting close to the bed of the lower jaw.
Investigate this: 
1.Pull your tongue far back toward the throat. You might notice your jaw sliding back and your airways narrowing. You may feel your stomach contracting. Some people can feel a bit nauseous doing this (so don't do it too much!).
2. Press the tongue against the roof of your mouth. You may feel pressure in your sinuses or your nose. There will be an increase in tension in your facial muscles and your teeth might press together. Do you stop breathing when you do this?
Amazing! The tongue is a powerful muscle! Try this out to relieve jaw and tongue tension. If anything it will put a big smile on your face!

With our fast paced life and high personal expectations, we tend to carry a lot of tension in our jaw. This usually involves our tongue being plastered to the roof of the mouth and/or pulled back toward the throat (more about the tongue in my next blog) and our jaw clenched. 
TMJ Dysfunction is a broad term often associated with: pain in the muscles involved with chewing, popping and clicking noises in the jaw, grinding teeth at night, and headaches.
From my clinical experience the 2 main causes of TMJ dysfunction is stress, and misalignment.
What happens to the body when we are chronically stessed? Think of a flight/flight response and you get the idea.
Misalignment can be influenced by many things: scoliosis, trauma to the jaw or teeth, and postural/behavioural habits. 
Do some of your own detective work:

Take a look in the mirror to see if your lower lip is shifted to the right or left of your upper lip. This could be a clue to an imbalanced use of your jaw.
Do you tend to prefer one side of your mouth to chew on? Do you find yourself tilting your head one way a lot?  Do your headaches start on one side of your head? All these indicators could be contributing to your TMJ issues. By knowing what you are doing, you can change what you do!

Try this short YouTube lesson from Feldenkrais Practitioner Cathy Paine to ease some of your jaw tension.