I can’t find the video I followed originally but what I do is pretty simple. I lie on the floor with one hand on my chest and one hand on my belly (just below t

I can’t find the video I followed originally but what I do is pretty simple. I lie on the floor with one hand on my chest and one hand on my belly (just below the sternum). Then I breathe paying attention that only the lower hand moves, ie that I’m using my diaphragm. I put the weights (small metal plates) under the lower hand to add resistance. I recall seeing some papers explaining the mechanism being related to how the diaphragm kind of wraps around the oesophageal sphincter, so strengthening it helps it close.