Dude. Tongue rings are gross. Same with those "studs" things, too.
Now, I'm not saying they're wrong or indecent or only punks get them or anything like that. Nor am I really even saying that they make you look ugly and worldly. But when I see someone with something sticking through their tongue, my gag reflex kicks in.
There is metal! In your mouth! Sticking THROUGH your tongue!!!!
Maybe that's just me being and old codger, but ick. Ick ick ick ick ick.