Decide what you will use to add the sparkle. Most craft stores carry gems in every color imaginable. Choose a gem to match the rest of your costume, and make sure it's the right size to fit comfortably inside your belly button. Rhinstones work great too, and add plenty of bling-bling to draw attention to your midrift. Simply dab a small amount of eyelash glue or body glue to the back of the gem and stick it right inside your belly button. Hold the gem in place for a few seconds to make sure it adheres well.
If you want the look of a true piercing, go with a dangle earring. Remove the hook or post from the back of the earring using needle-nose pliers. Attach the dangle to your belly button using an ample amount of eyelash glue. To complete the look, attach a small rhinestone above the dangle, giving the appearance of two parts to your "piercing." Try a few belly rolls to make sure you've applied enough glue to hold everything in place. Make sure you keep a bottle of eyelash glue handy for quick touch-ups or reapplication.
