I used to have this if I stopped myself passing gas (as you do in company), and it was embarrassingly audible. I haven't cured it, but I'm very careful about food now (what I eat and how quickly I eat it) so that it hasn't been such a problem since. Do you generally get a large quantity of gas? If so, can you try to identify what is causing it and remove it from your diet, or is it more complicated than that?