How do you do a belly grinder?

Two inflate your belly there are two ways:1. Drink some water until it hurts. Next time, drink more. Each time you drink more water.2. Take a bike/aquarium pump. Insert the part that blows air into...

grinder (a machine that processes materials by grinding or crushing)

I could play with it but people with normal bellies can (like me). Also, most people choose not to because that is just a little odd. I can do what most other people can do too. For example, I can...

gas, probably

probably because it's shaped like an old-fasioned soup pot/cauldron.