There are things that set us off and things that calm us down.
A breath and the finger rub of the thumb and forefinger creates a parasympathetic response. This is a calming response that can be linked to a time when we are calm.
When in a peaceful place in your mind create this anchor to calm by breathing peacefully and rubbing your thumb and forefinger together. A good technique to use when in a stressful situation to bring back some calm.