Lay down that frost

Our guild was attempting 25 man Deathbringer Saurfang for the first time the other night.  After a couple wipes a guildie (who shall remain unnamed) attempted to give the raid some instruction on how to handle the blood beasts.

I was told to "lay down frost" and "slow the mobs". 

...I'm an arcane mage.   (And no, they were not getting me confused with a hunter.)

So I think I was being directed to either frost nova the mobs in place (which I cannot cast at range as an arcane).  Or maybe they meant for me to slow the mobs with blizzard (but an arcane mage doesn't have improved blizzard so that would be impossible.)

At any rate we downed DBS last night and I didn't have to "lay down" my frost to do it.  Woot.