The ring that is embedded on
your wallet from having a condom in there for a period of more than 6 months.
This happens when you try to prove to your friends, or anybody that you get laid. You occasionally pull it out to show someone, but stupidly put it back in the same place so it can make an indent in
your wallet.
This is usually prevelent in the High School age group. For some reason, future
computer science Majors and Dungeons and Dragons' Players seem to have a high instance.