Ive had my Belly button pierced, but I didn't have an attachment to it. Was jut another place to get pierced lol out of all the piercings I've had (and theres been quite a few!) the ones I had trouble parting with was my 'Vertical labret' but I took that out because my bird liked to yank it and it started migrating, and my arm piercings, because they were crazy, but I tore them out by accident on my car seat (was cleaning the car and accidentally bumped the seat release, so jr ->-bleeped-<- the seat up with two of my six piercings caught) I made the choice to get rid of the undamaged four because it wasn't the same

That being said, I have both sides of my ears done ATM and was tossing up about them being too girly, but I like them so ->-bleeped-<- it, if you like your belly button piercing keep it, it's not like the hole won't still be there, and it won't close up anyway, you could always take it out if you were going shirtless for whatever reason

and heaps of dudes have it done, sure it's mostly flamboyant ones, but there's NOTHING wrong with that, and I'm sure some tough as nuts dudes have it done too.