Suppress Enemies within 5-8 Radius on Close Range Kill.
Your Secondary Attack cannot be interrupted and loses 20-50% of Secondary Attack Movement Speed penalties.
Charge attack with right mouse button. Shoot the ball into enemy horde, booooooom. You can use any melee weapon, just make sure to pick the right staff.
Aim for legs. If enemies don't have legs anymore, they can't reach you! They are likely dead anyway at that point.