How do you stop your stomach from rumbling?

I know this has been asked a million times but I couldn't find anything. Anyways I eat a good breakfast. But it still fricking growls SO LOUD. Today it didn't that much but it felt like it was going to so I was practically punching my stomach the entire day, lol. And for some reason it growls extra and way louder in library than anywhere (I only have library a day a week). I don't have any breaks and I can't eat in cl. But any tips (to make it go away not try to cover it up) would be greatly aprieciated (spelling, :)).