Check that out, should answer all your questions.
My rotation (first check my spec/glyphs in the Alliance link in my sig [keep in mind the online gear viewer doesn't show reforging] - also, glyph maul and macro it to every move, ie:
#showtooltip Mangle(Bear Form)
/cast Mangle(Bear Form)
like that - keep in mind I have that macroe'd to every single attack I have [not the shouts and all, or FFF])
3 or more targets:
Thorns yourself-> Bear Form, Enrage, FFF main target and enter fight, Swipe, Thrash, Demo Roar, Barkskin, Lacerate x1 -> Pulverize (just to get the buff up for Savage Defense procs). Then I just spam swipe and use thrash whenever it is up while refreshing demo roar whenever its about to fall off and 1 lacerate into a pulverize if buff is dropping, and barkskin again if the fight goes that long. Each time the main kill target dies and you switch to the next mob, FFF it. I have no problem holding the mobs as long as I mark the main one I'm targetting as the skull. If i start to lose threat I just mangle them too, or since my FFF is on a mouseover sometimes I'll FFF the other mobs in between swiping and thrashing, while still keeping my current target.
Thorns/Enrage, FFF while running in, Mangle, Demo Shout, Lacerate x 3, Pulverize, Mangle, Lacerate x 3
Keep Mangle on CD and use it FIRST every proc
Keep Demo Roar up
Keep Pulverize buff up to proc Savage Defense
Keep Lacerate at 3 stacks and let it tick until Pulverize buff about to fall off then pulverize again and immediately refresh lacerate stacks to begin ticking again
Use Swipe if Mangle and Maul are on CD and Lacerate is at 3 stacks while pulverize buff is up
Use Barkskin whenever it's off CD (pref save for heavy damage phases but it's only a min CD so use it as much as possible)
Growl or FFF during movement or knockbacks
I have 0 problems with aggro and I'm tanking heroics