I have this issue, and also, allowing my hands/forearms to not be very close/in contact with my core after turn completion and across the wakes. Too much space! To me, it is another symptom of the same thing. In snow skiing, I absolutely am controlling my skis with the balls of my feet ( as @AdamCord describes), and the fronts of my boots with shin pressure and active, engaged ankles. Out on the water, I think I can feel some good equal pressure on my feet at times, and can feel tall at times, but in reality get squatty, and end up back on the rear foot a bit. Particularly in my pre-turn, and entering the turn on 2, 4, 6. (LFF guy here).
I used to think about pushing my hips up by doing things like pinching up my butt cheeks, forcing the hips forward, or attempting to pinch my shoulder blades back. That tended to make too much lumbar curve for me, which as someone with a formerly blown L4/L5, I cannot do. Also, it misses the mark and goal I think.
Now I am just attempting to stand up more at all times, and shift my hips forward over my feet rather than push them. (to me there is a difference). And learn to make sure any lean and leverage is away from the boat, rather than back in terms of fore and aft on the ski at all.
So right now, (and I haven't even been on water yet, we still have snow in the yard), that is my approach, and my primary goal this year. Stay taller over the ski with hips over my front foot as best as possible, arms, elbows and handle with contact to the vest, legs, core. Definitely a work in progress for me.