It may stick outwards (an outie) or inwards (an innie).
Useful for catching spooge but tends also to collect nut butter and lint.
When they snipped it off, it made an ugly scab, on your belly whuch healed and left a little knob about the size of a button. If they didn't trim it enough, it's an outie, and if they trimmed it weel it's an innie.
The belly button collects little balls of fuzz called nerds.
If you poke somone in the belly buttton, they might laugh like the Pillsbury dough boy.