Code:
 
/click BonusActionButton#
The # being the number of the ability. All one word, took me a while to figure that out, kept putting a space before the number. I used something like this for ToC as well. The horses inside ToC didn't respond to the same macro's used on the dailies when I called the spell name (/use Shield-Breaker). Joust & Defend are on different cooldowns, so a macro with both will make sure Defend is up 100%.