Well I have no clue really. I don't quite know the name. But get into the missonary position, and then have him get one leg up on each sholder so hes kinda "on" top of you. Hes tilted on top of you with your legs in the air. I don't know if I explained this well, but it hit my GF's spot and she goes nuts when I trust fast, the position basically just allows him to get deeper, thats all.

I don't know if you've tried or not, but just trying to help...im sure others will be better at it lol.