I sometimes call this anti-stress or re-patterning breathing. Once you train yourself to breathe deeply every time you feel stressed out, you will really see a change and have a greater awareness of how you hold your energy. For relaxation breathing to become instinctual, it takes practice and awareness. This is a good one to do discreetly when in a meeting, before you make a tough call, during a stressful conversation or anytime you feel crazy. You can do this anytime, anywhere.
Take a deep slow breath in… and out… in… and out… in… and out. I like to envision all tension, stress and negativity falling away with every exhale.