Looked for this but found nothing. Hopefully I don't fail at searching.
While going through Ulduar tonight, I discovered something interesting regarding my meta gem and Totemic Call.
Totemic Call destroys your totems and returns mana to you. It can also trigger the +600 mana effect of the meta gem Insightful Earthsiege Diamond.
What most shaman know about Totemic Call is that for a few moments after you call your totems back, you can recast this spell even if totems aren't active.
The exploit here is that you can often trigger the mana effect from the meta gem even when you cast Totemic Call with no totems out by simply spamming it after you pull them up. You have a fair chunk of time in which to do this, as you don't get the "Invalid Target" message for roughly 10 seconds after the initial use.
This isn't an insanely OP exploit but it might help someone in a pinch. Hopefully.