I like what is best for her, so I'm flexible. Alas, women never tell you what they want, so I guess. For me, doggy is hot early in the evening. Later, I get tired, so her on top works best. Her legs on my shoulders gets me in deep, so I get lots of exciting verbal comments. As for me, pace is way more important than position. Slam, slam, harder, harder is no fun - I like an easy pace until orgasm time.