What is the hotkey for the spell next to the right click spell?

How do I activate it? Here's a picture of what I'm talking about. http://i.snag.gy/ODKx1.jpg


That spell overrides your current right-click spell by using TAB (default bindings).

You unfortunately will need to TAB between those two spells to use them.

If that proves too slow for you, you'll have to bind it to another key. Notice you already have it bound to 5.

The answer to this question covers the keybinding issue.