Here's how this macro works:
Once you enter each type of mount you want to use for the type for flying and riding, such as if you are in a zone you cant fly in like Pandaria sub level 90. Just click the button and it will mount the most appropriate mount for the place you are in.
Next week I have a variation of this same macro for Shaman that is even more useful and will save 5 slots on your action bar.
This post is associated with the Nonmail's Nutz the podcast, episode number 25. If you have any Macro requests or suggestions email me at