I'm suprised your having trouble aoe tanking off chain lightning. My druid isn't having any issues against my mages aoe or priests.

How many adds are we talking 1-2, 4+ etc?
Are you rage starved? If so drop maul and just swipe. You'll have a tad less threat on your main target but if your rage starved maul will cause you to lose adds.

Edit: I hate to ask but how is your druid specced? Is it an appropriate spec for tanking/aoe?