Corset piercings are actually just a specific configuration of surface piercings or even just temporary play piercings. They are usually placed in two columns vertically along the back, mimicking the position of the eyelets on a corset. To heighten this illusion, string or decorative lacing can then be threaded through the jewelry.
While these are typically placed on the back, the term has more recently come to be used to broadly refer to any paired ladders of piercings which can be laced together. Corset piercings have become a common element of fetish performance groups.
It should be noted that these piercings are almost always temporary, and tend to be removed shortly after the event they were pierced for. These piercings are usually performed with captive bead rings or even just hypodermic needles; it is not reasonable to heal this modification utilizing this type of jewelry. It should be noted that if left in, much of the jewelery used in corset piercings has a very high risk of rejection (highly visible in the second photo below), which will most likely leave scarring. Therefore, fairly prompt removal is necessary with most jewelery used. Some corset piercings have been sucessfully healed using carefully-placed surface bars with bondage/slave rings, but the location still leaves them prone to rejection. These pierceings can also be done with microdermals switching from a flat head to a captive head and laced for short periods. Keeping the captives and lacing in place for prolonged periods can cause rejection whereas the piercings can be maintained with the flat heads in place.