This is a belly button. When you are in a womb, food and nutrients enter your body through the umbilical cord. When you came out, the Doctor cuts away the cord and slowly, it shrinks and drops off, leaving a hole in your belly. But you cannot put anything into it because its sealed off. Yep, the Belly Express is closed.
It does not do anything special except to gather fluff and give you a stink when you dig it with your fingernail after your nose is 'clean'