This video is based upon an excellent paper from Czechoslovakia
https://www.rehabps.cz/data/GERD_Pape...
The paper demonstrates the postural correction that makes the oesophagus (and presumably also the internal oesophageal sphincter) regain normal relaxed function.

It also demonstrates the best style of diaphragmatic breathing to close the oesophageal sphincter and prevent hernia and acid reflux/heartburn.

This same style of breathing also happens to be the best and most comfortable and stable style of diaphragmatic breathing that I have yet found. (And believe me, I've been looking for a while!)