Seriously, on a daily basis I'll either bump my head or various other body parts, drop stuff and then drop it again, stumble over something and combinations of all of that.
Send help.
Edit: thank for the suggestions, I will start by focussing on what I'm actually doing at the time and try to be more active - I work from home and sit a lot.
An attempt at a serious answer (I'm not a doctor). The blood vessels that connected you to your mom during pregnancy dry up and become ligaments connecting the inside part of your belly button to your liver and bladder, so that's what's on the other side.
Your skin/body doesn't dent and pucker like something made out of tin. It's stretchy and resilient. If you put a vacuum nozzle on your forearm, sure, the skin will get pulled into it a bit, but when you take it off, the skin will return to normal (maybe with some temporary swelling).
So with enough suction, you might get your belly button to pucker out, but it won't stay that way, especially with the ligament pulling back. On the other hand, as others have mentioned, you can get it to stick out by pushing on it from the inside, as happens to a lot of pregnant women when the baby is pushed up against it. Even in those cases it goes back after the baby is born though.
I was only looking at your reply in my inbox, so had to do the "show context" thing to see what you were talking about. I made my comment on the thread about using a plunger to turn an innie belly button into an outie, at least I'm pretty sure I did. I've been seeing a lot of comments that are clearly in the wrong thread, so apparently there's a bug, but I don't know what triggers it.