Admittedly a little funny, this breathing technique helps us to fully empty our lungs. We add some sound (counting) to our exhale and keep going until there is no exhale left. Then we drink in a full inhale. It is a quick way to keep carbon dioxide in our body for a little longer so that when the oxygen floods in with the inhalation it can be distributed efficiently.
Suggested practices you can use to follow-on or explore similar themes
10 Minute Flow
10 Minute Sit
Peace Mantra