1. The guy above me is retarded. It doesn't hurt at all. It's a little pinch.
2. You get a hole punched in your tongue and you can then put all sorts of little things in there from french ticklers to double ball french ticklers. Serves a valuable purpose in the bedroom whether male or female.
Something others have to express their artistic nature but I'll always see them as yet another fad people immerse themselves in to be part of the "in crowd" involves paying another individual a sum of money to inflict intense temporary pain. Later you purchase a shinnytrinket of some sort to jam in the hole and prove to everyone else how badass you are.
Admission or outright advertisement that you will perform oral sex on just about anyone. If a guy has a tongue ring, a dick has most certainly been in his mouth.
Johnny: Did you hear Trent got his tongue pierced?
Brad: Dude, he's got a tongue ring? I didn't know he went fag.