Sprung

A Sprung Piercing is an extremely deep piercing that passes from just below the tongue (inside the jawline), straight down, and out the bottom under the chin. It takes a great deal of time to heal and often "seeps" even a year or more afterwards. Many piercers feel that due to the invasiveness of the sprung piercing, it should be avoided.

It is named "Sprung" after the first person to get it done (and publish that fact), by the late Mick Noland.