The certified flight instructor (CFI) and student pilot were practicing hover autorotations. The CFI noted that the student had expressed difficulty with sufficient pedal inputs in the past, and the helicopter would yaw excessively to the left. The CFI demonstrated the maneuver to the student, showing him to establish the helicopter in a 2-foot hover, look outside and pick a reference point to maintain heading, position his hand on the throttle to roll it off, and as throttle is rolled off, prepare to apply right pedal to counteract the left yaw. The student pilot then assumed the controls and configured the helicopter for the hovering autorotation. The CFI had his left hand on the collective, his right hand on the cyclic, and his feet were guarding the pedals. The student counted down, "three, two, one…" and rolled the throttle on while adding right pedal. The helicopter yawed hard and fast to the right and the student pulled aft cyclic. The CFI attempted to regain control of the helicopter; however, the tail cone contacted the ground and the helicopter came to rest on its left side. The CFI stated that there were no mechanical malfunctions with the helicopter, prior to the accident.