Q. I am a slim man 6'1" 189lbs and my wife is 5'8" 425lbs and what I was wondering what are the best positions I can use to give my wife something very special in intercourse.
A. Any position that keeps excess weight away from her pubic area will assist in penetration of an obese woman. Therefore, it would be helpful to have her butt slightly elevated on a cushion or pillow. Try her laying back at the edge of the bed (as in the Butterfly), and/or with her knees drawn up and wide (The Deckchair or Deep Impact ).
Another option is to try the Doggy Style Family of positions; they involve you approaching from behind so she will be able to present herself more easily for penetration (especially if most of her weight is on her front). The possibilities include the Kneeling , Standing, and Turtle positions.
Remember to experiment and see what works for you both … many of the other positions might also work with a little adaptation. Good luck!
(To see the full discussion of a thread on this topic please see Making Love to an Obese Woman in our Forum.)