Remember, the rudder controls the nose of the heli. Left rudder causes the nose to go left. Right rudder and the nose goes right.

Now, here is the trick. Since the blades are clockwise, without a tail motor (or any thrust from the tail), the heli will go nose left. Just the same as if you pushed left rudder. So, when you want to the nose to go left, all the tail has to do is slow down or stop the motor and the torque from the main blades will cause the nose to go left.
In order to go right, the tail motor has to overcome the torque, thereby requiring more thrust from the tail and hence, the tail motor (and blade) speeds up!

Sound like normal operation in that regard,
Michael