How do you shrink on Free Realms

If you buy a special card in the real world or if you pay with Station Cash, you can get a sandwich called the 'Shrink Sandwich'. This sandwich allows you to shrink to a smaller size than the usual player. No, you will not be microscopic, but you will by a little higher than half of the usual player. I have the sandwich myself and it is single use, so I am waiting for the right time to use it.