Unless "chin" is signaled, "high" usually begins when the guard with the ball waves the other one through.
5 rubs off of the cutting guard to the elbow.
If the guard waves 2 through to bring the post to the elbow to begin "high", 1 doesn't always have to pass to 5.
He may choose to spin and dribble instead at 4 to initiate a backdoor/fill or flare option.
If 1 passes the ball, he uses 5's flare screen.
Top flare situation begins.