I think it would be a toss up between doggie and her on her back with her knees over my shoulders. Doggie gives a great veiw of her ass and allows me to spank her at the same time , it also makes her feel just that much tighter. Knees over the shoulder gives a great feeling of control, and allows me to hit the back wall which fees great for both of us. On the days she is really flexible I can also kiss and play with her tits.