Heavens, I feel for this man.
Anyway: squeeze, stretch and relax.
This can be done with any part or parts of the body. Let’s take the hands. Make a tight fist – or possibly squeeze very tightly a couple of wrongly printed pieces of paper into a ball in each hand. Release the fists or paper ball. Now stretch your fingers out as wide as possible. Then let the hands relax completely. If you are alone, you can do this with your face – scrunch it up tight for about 5 seconds, then open everything wide – eyes, mouth, exposing the teeth, for about 5 seconds, then relax your face completely. If you do this in public, it will scare children if done properly.
Of course, you can do this with your feet, your shoulders or any combination.