Balancing horse while in two-point
I am battling the "creeping heel" problem and my instructor suggested a little two-point to stretch my legs and help with heels down. I admit it's not something I do that often outside of lessons, but while practicing on my own today, I noticed it seemed like my mare was having some trouble balancing us while I was up in two-point. I could feel her physically stumble on the front end underneath me, and hear her pounding away on the forehand. I have every reason to believe I was probably perched too far forward and sticking my bum way out, so that could certainly be the bulk of the problem. I don't have my hands resting on her neck or anything, I can carry myself, but it still seems clear I've messed with the center of gravity.
Does anyone have any advice for helping my mare stay more balanced while I'm working on this exercise to get my leg in a better position? Her biggest problem right now is being too heavy on the forehand and not working from behind, so I certainly don't want to make her problems worse while trying to work on myself, which seems so counterproductive.
Unfortunately I don't have any pics/vid right now, but maybe someone could post *good* examples on position to avoid a heavy-on-the-forehand horse while riding in two-point, and I can have a good mental image going into my next ride. What suggestions do you all have for me?