Just make a macro, and use that as the macro text.
Or press Enter, and paste it into your console.


I personally have a Buff key, which for a pally might be:
/castsequence reset=5 Seal of Vengeance,Null

And on another toon, maybe:
/castsequence reset=5 Water Shield, Flametongue Weapon,Null

And will periodically spam this, until the spell flashes stop occurring (as in everyone reaches the Null section of the sequence).