Play Piercing can be done for many reasons; Enlightenment, aesthetics, fetish & sexuality, photos, performances/demonstrations, etc. In all of these cases they are temporary and removed a short time after being put in. Play piercings can be done by inserting multiple hypodermic needles or jewelry can be used in some cases as well.
Corset piercings generally fall under this category, but they can also be done with permanent intentions by using carefully placed surface bars with slave ring attachments to lace through.