Is it normal to do this with my butt?
Okay, this may seem gross, but when I was a kid, and every once in a while now that I'm an adult, I'd do this thing that enabled me to suck in air through my butt. I'd pull down my pants and undies, stick my butt in the air, and relax my anus until it sort of opened. Then I would suck in my gut, and air would be sucked in. Then I'd just hold it in for a while, then fart it back out.
Is this normal, or am/was I a weirdo for doing this?