Best position is her lying down, legs together to one side. Her ass is out to the side, thighs are squeezing, and you hit her g-pot with every thrust because of the angle. If any1 wants a map, I'll sketch it out. I found this to work wonders by accident with an ex gf. I just put her into that position and she came supposedly harder than she ever came before. And she made me memorize the position and never forget it. lol. It's good shit.