Duck stance

Duck stance means that you have a foot position were your feet are pointing slightly outward. See fig. below.

When standing in this position it is easier to do squats without having your knees falling in. See fig below.

By pushing your outer ski forward and extending your leg you create a pressure in your heel cuff which in turn creates a bending moment that bends up your ski on edge and stabilizes it.
By pulling your inner ski you create a pressure in your tongue of the boot which gives a bending moment that bends up your ski on edge and stabilizes it. See fig. below.

The good thing with this is that you engage more of your thigh muscles in the banking of your skis. When having a normal mount you have to stabilize your skis banking with your knees working perpendicular to its natural function, which in turn sets greater demands on the skier’s skills and physics.