This is the basic 2-step I'm using on my bear tank (bear + 4 shams):

step-1:
#showtooltip
/castsequence reset=target/5 Lacerate, Lacerate, Lacerate, Pulverize, Thrash, Swipe (Bearform), Maul
/use 13
/cast Enrage
/cast Berserk

/step-2:
#showtooltip
/castsequence reset=combat/8 Demoralizing Roar, Mangle, Mangle, Mangle, Mangle, Mangle
#/use 14

Ususlly generates enough rage to manually apply additional Thrash and Maul.