In the quest item section of the inventory there is a dragon stone (which allows you to teleport to the battle tower from most places, move between platforms and return again where you left off), as well as a dragon morph stone (which toggles between human and dragon forms). You can either use these stones from your inventory, pause the game and hit a shoulder button and use them from the menu that comes up, or assign them to a button or pad direction.
I assigned the dragon stone to the left d-pad direction, and the dragon morph stone to the right (need to assign hotkeys in human and dragon form).
