PUSH shots are a great option for changing the angle (shoot around defenders) in 1V1 attacking situations. 

The PULL IN portion is not a requirement, in the clips you'll see different techniques. When the puck is carried far enough behind the body. The pull in isn't required, only a slight push out. 

This clip shows a variety of NHL players utilizing the push out angle change technique along with a very simple introductory drill we've used at our shooting camps and team sessions for many years. 

The drill can be progressed to include live defenders & different attack angles, However, this is a simple way to introduce the technique and get a high number of reps quickly, allowing players to figure it out.