Assuming a standard pitch shot off a reasonable lie, this is what the club would need to do in order to achieve the ball flight.
Narrower arc
Firstly due to the shorter clubs (and the possibility you are holding down the handle slightly on smaller pitches), the radius of the arc is smaller. This will mean the length of turf the club is contact with will be shorter.
Lower on face
By making contact with the ball slightly lower on the face than for a full shot, it creates
Shallow divot
In order to find this slightly lower impact location, and also improve distance control by having a more predictable interaction with the turf, I would aim to very lightly scalp or bruise the turf on pitches. Angle of attack might be as little as 4 deg down.
Shaft lean
Expert pitchers would typically lean the shaft forward by 10-12 degrees, which in combination with a -4 deg angle of attack would allow a them to launch a Sand Wedge at 30 deg.
Path
Some of the best pitchers in the ball draw the ball using an in to out path. This doesn't inherently create more backspin but this shallow angle of attack does tend to help the low impact location mentioned above.
For simplicity however I advocate a neutral path as tilting the axis of the ball with a draw or fade swing potentially adds another variable to distance control.