Deflation theory

Here’s a mystery: why do some people burp at the same time that they “break wind”? It would seem that one escape of gas would do the trick — sufficient deflation! And yet there is a healthy subset of humans for whom the one method is often accompanied by the other. I have several theories — one involving the shape of the lower intestine, another hinging upon certain vicissitudes of gut flora — that I am looking to expand into book form. Stay tuned, everyone.