Coach out top passes to attacker 2 on the wing, defender 1 closes out from a gap position, play to a stop or score with a limit of three dribbles (or two at higher levels), then 1 immediately returns to his gap position and defends the next attacker (coach passes a second ball), continue until he has defended all the other players, then switch the defender.
1 must move on air time and not sag, hoping for a missed shot. Close out with high hands, but shoulders lower than the attacker's shoulders.
Repeat the drill with attackers in a corner, or with coach on a wing and attackers out top.
See Defending - Duke driving line, UConn stops, 1 on 1 - Coach as passer, Tom Crean 3-minute.