Engage the rear brake on for 4 seconds and off for 4 seconds.
Feel the stability of the motorbike when the rear brake is applied
Vary the throttle accordingly - Apply the rear brake you will need slightly more power from the throttle. Disengaging the rear brake, you may need slightly less throttle.
Throttles may differ from one bike to another. Know your throttle, throttle is gradual in millimetres.