Breathe in deeply.  Try inhaling for a full five seconds.  Fill your lungs.  Use your diaphragm.  Let your belly expand.  Hold in the air for a few seconds before exhaling.  Exhale completely.  Give a few short exhalations after you’ve exhaled to try to get out as much air as you can.  Feel your belly dip.

Repeat.

This is good for you.  It gives your body more oxygen and your reduces feelings of anxiety and stress.