The arguments over using a straw are nuts, but we get it.
The topic creates almost as much passion and drama as the "which surgery is best" debate. Let us explain it to you.
We have all used a straw in life so let's talk our way thought this. A straw is a column that you draw liquid through before swallowing. That column is filled with air and then you create a seal so you may suck and replace the air with liquid. IF you swallow that air that fills your mouth before the liquid it can send that air into your pouch and intestines and be quite uncomfortable. BELCH burrrrp belch burrrrrrrrrp burp! That is the AIR you have swallowed building up and releasing.
Next time, suck through the straw and THINK while you are doing it. Swallow the liquid and not the air. If somehow you can't manage this maneuver and the belching doesn't stop - DON'T USE A STRAW ANYMORE. If you can drink through a straw without GULPING air with your liquid and belching, it's fine to use one.
Doctors say 'no straws' because they can't judge your sucking skills by looking at you and err on side of caution. That should put this one to rest. We have talked thousands through the straw debate. If this helps solve your belching issue we are happy, if not... oh well.