Set two cones up near the half court line or you can use other lines on your court.

Player 1 start out near a slot.

Player 1 backpedals to the cone. Once at the cone they defensive slide to the next cone. Once at the final cone sprint to the 3 point line and catch and shoot.

Player 1 backpedals to the cone behind them and then defensive slides to the next cone and sprints into the 3 point shot.

Repeat sequence.