What does A it up mean?

A it up meaning in Urban Dictionary

Used in the newest Super Mario Brothers the Wii advice. If you're on 2 player and you're dropping to your demise you might press the "A" key you remote, producing a bubble around able to be popped when you are struck by any object.This expression may be used if you tend to be going to push the "A" option regarding the remote, to alert your friend that you are going to "A."