Have the goaltender start in his crease laying on his back (alternate head facing forward and facing backward). The shooter should be at the mid-top of circle level but should move around while the goaltender is on his back.
When the signal is given, the goaltender should first get up, and while keeping his eye on the puck and his body between the puck and the net, get into position to stop the shot. The shooter may shoot before the goaltender is in position (as long as he is facing the shot and will not be injured).