Staying Square to The Puck

Good explanation of how to stay square as the play develops down the wing and how the goaltender stays square and moves with the puck while staying at the proper depth. 

All of the information is correct and well presented, the only caution I would add is that when the puck gets below the circle as at 2:50, the goaltender should back up to the post to prepare for the inevitable pass across or the player driving behind the goal line. 

When practicing this drill, it is also important to immediately gain a solid anchored post position as soon as the pick goes behind the goal line. 

Source: GotttaLoveCTHockey - It doesn't say who the presenter is, but he does a great job.