We're up to the Illidari Council in Black Temple now, the High-King Maulgar equivalent fight in Black Temple. There's four mobs to tank. The paladin needs to be tanked by a spell reflecting warrior and the mage has to be tanked by a spellstealing mage. The rogue is well tanked by a druid; he vanishes and when he comes back you need to quickly hit him again to regain aggro. But sometimes he's melee immune, so a Moonfire or Faerie Fire can be a big help.
Finally there's Lady Malande, the priest. She doesn't really hit hard; her main thing is that she casts all these nasty spells you need to interrupt. The usual advice is to have a warrior tank so he can Pummel / Shield Bash and interrupt. But druids can interrupt too, with Feral Charge!
Circle of Healing is the big thing you want to interrupt; it's a long fight and you can't afford her to heal the bad guys. Best to put a rogue on Kick duty for that. But she also has a nasty Divine Wrath that can kill folks pretty quick. And for that, why, a feral druid can interrupt that and help out the healers.
The trick is staying at range to use Feral Charge. Normally we don't have that luxury when tanking. But Lalande almost never melees; she's content to stand at range and cast. And no one's DPSing her too hard in the usual setup, so you don't need to generate much threat. So hit her a few times at the start of the pull to get aggro, then hang back at 10 yards and just hover over your feral charge key waiting to interrupt. Voila, you're like a rogue who can tank!
The other fun thing about tanking Malande is that since she doesn't really melee, you don't need to be in bear form when tanking her other than for the extra HP. So you have time to innervate, battle rez, etc. Beyond that, when tanking Malande just be sure to watch out for all the other silly tricks. If she's melee immune you can't do a damn thing, so don't bother. If she has her reflective shield up don't hit her. But mostly you're tanking a target that no one is hitting, so you've got time to play all sorts of tricks.