When coach yells "stop" or "go", 2 immediately closes out on next attacker 3 who gets a pass from coach (rotate attacker to defender). 1 passes the first ball to coach. If 3 is a post player he will start closer to the basket, or post up. Attackers need to be ready to shoot off the pass - load the gun.
Variation - coach passes from the wing, attackers are out top.