Diablo Game Questions fury generation on IK/wastes rend barb?

How exactly can i properly generate enough fury to spam abilities in order to get the cooldown on Wrath of the berserker low enough to have decent uptime?, once i swapped out the fury of ancients shoulders for lamentation in the cube i never have enough fury to get WOTB back up before it runs out with 50% of cooldown left, any help is awesome, thank you!