Tongue piercings are one of the most septic-prone piercings out there; even more than belly buttons. I knew one woman whose tongue piercing got so infected the swelling started to close around the piercing; but to remove the stud would have mneant the flesh woudl seal in the infection and make it worse; she suffered for weeks...our mouths are NOT clean places and that is why lip and tongue piercings are kind of nasty...Ironically enough, genital piercings are far les prone to infections; urination is one reason they are what is called "self-cleansing" (this is a piercing term), as opposed to other areas where one must clean the piercing repeatedly to prevent infection.
I was engaged to a guy with several genital piercings. He later got a tongue piercing.
(shrug) Nothing special about it either way. There's metal where there wasn't any before. But no new super-powers. I think he thought the added attention might get him more sexual attention; perhaps it did. But I don't think piercings in and of themselves enhance sexual performance or pleasure.
Not in my experience anyway. Though I do like nipple piercings on men.