Cues for lead initiating rotation

[Buckley]

I have experienced many instances where as the lead official in 3-man mechanics, I am either rotating too late or too early. Because of this, shots are going up as I am in my rotation, thus causing confusion for my partners or me making calls on the move. Other times, because I am tentative to initiate a rotation, I am staying put, and the "C" is left officiating all the action. What types of specific cues do you use--besides the ball 'settling'--to help you know when to initiate a rotation.