How do you make your stomach growl?

There are lots of ways to do so, I bet, but the 2 ways to make your stomach all growly and grumbly and rumbling-like i that follows:

1. eat lots of food

2. eat something bad which will make your belly upset and it'll start growling a lot

3. don't eat anything for dinner. then, while in bed, try to record the growling of your stomach.

4. you could swallow air