Like Robo said, she needs to sway her hips backwards, bend forward at the waist, put more of her weight on her left foot, and lean into it. It also help her to raise her right elbow parallel to the ground. This creates a deeper pocket in your shoulder where the butt stock goes. Warning, be diplomatic here, most women don't like being told what to do and she looks like she works-out on a regular basis.
By the way, that's me with my Arnold mask on.