Like nodding your head, opening and closing your hands can be used to guide your nervous system to a calmer, easier rhythm.
Give it a try:
Bring the tips of the fingers on your non-dominant hand to touch.
As slowly and lightly as possible begin to open your hand just a little bit.
Reverse the movement and slowly bring the tips of your fingers together again.
Continue to bring the tips of your fingers toward and away from each other as if your hand were a flower bud opening and closing in slow motion.
When you have found slow, smooth rhythm with your non-dominant hand, try it with your dominant hand.
Then, try it with both hands at the same time.
What happens to your breathing?
What happens to the tension in your jaw, neck, shoulders, face, etc. as you continue to open and close?