Ive signed up to this page just so that I can share my insight.
I think Ive found something that works - for me at least. Ive had gas problems when nervous for about 12 years now...and its stopped me from doing most things. Uni was such a struggle...I tried everything - medicine, teas, exercise etc. didnt work.
You know what does work? Doing a poo. Honestly, every morning before you leave the house do to the toilet. Clear your bowls. You will find that when you get nervous during the day there is actually nothing in your stomach to start these farts off.
I realised actually, I dont want to fart, I want to poo, so if your feeling the gas a-coming, go to the toilet and do a poo. Trust me, it has worked wonders for me - and now Im studying my masters and I go to every class and letter without the fear.
Hope that helps....