Doggy for sure. Get to bump up against nice ass cheeks while getting a good view of your partners anus.
My favorite has always been guy on top, with her legs/ankles resting on my shoulders. Lets my cock go deeper inside her, love the feeling of dominance over her especially when I cum.
My wife and I used to explore a lot of positions in our love making, but as we aged, our favorite position was her lying on the bed prone and my entering her from the rear. She would usually rub her clit and have powerful orgasms that way.
