Can anyone give an accurate description of what's happening inside a baby's body when you burp it and what the various aspects of burping process (patting, rubbing, leaning forward, bending legs, etc.) do? Science references would be great.
All I can find is instructions on how to burp and anecdotes.
What I understand so far is that you're trying to get gas bubbles in their stomach to escape through a valve in their esophagus which is usually closed and that patting is supposed to jiggle the bubbles upwards towards that exit valve. Rubbing and bending might be to deform the stomach to dislodge bubbles stuck in folds.