Good morning,
This may sound silly, any may not even work for you depending on your condition, but when I am having a problem with gas in my stomach after a meal that I can't seem to get rid of I will usually crack open a can of sprite. I don't even need to drink the full can, just a few sips and I can usually get a good belch. As far as gas from the other end, I take some laxatives every day because of some meds that I take, so I don't seem to have a problem with that!