How come I have embarrassing stomach growling from holding in farts?

Why hold them? Passing the gas that accumulates in your intestines from swallowed air, bacteria etc is the normal way of removing it from your body. If you are holding it in you are causing gas and fluid to squirt back thru contracting intestines, causing your noises. Better to just excuse yourself and let it pass. See this website about reducing gas : http://digestive.Niddk.Nih.Gov/ddiseases/pubs/gas.