Chris Rocks says:
If a woman has a pierced tongue, she'll probably suck your dick. If a guy has a pierced tongue, he'll probably suck your dick.
Seriously though, a chick that knows how to use a tongue stud is a fine sexual partner indeed. I have been so blessed a few times, and can report without equivocation, it's a Good Thing.
A new thing (to me anyway) is tongue spacers. A friend of mine has a 1/2 inch translucent round plastic spacer in his tongue that match the ones in his ears. Light filters through them, and his ears glow blue or green or whatever color he has in his ears. His tongue only glows when he shines a flashlight through it, but it's kind of neat looking.