Octacleave.

[Sylvina]

So there are WARs worrying about not getting a 5th Fellcleave off, and the OP is saying she can get 8 Fellcleaves off.

Lemme tell you how. First, make sure your skill speed isn't too low so you can get the 5th one off. if your beast gauge is full when you get the 5th one off under inner release you'll be able to get 2 more off after. then pop infuriate and get off the 8th.