A peircing in one side of an upper lip. This peircing is almost exclusively seen on younger females, and most often contains a stud, rather than a ring. Named after the famous pop musician, who has a natural beauty spot in the same place.
Unfortunately, this particular peircing is associated with the lower classes, and with people of poor taste.
That girl should never have worn a yellow cubic zirconia in her madonna - now it looks even more like a zit!
People who are brave enough are known to approach a girl with a madonna, and casually tell her that she has "someting on her lip... just there..."