My first question is, are you trying to give yourself a fast orgasm or your partner? or both? . . for a guy, I believe it is better to have her on her knees, like she suggested, or you could have her on her back with her legs on your shoulders... For a woman, I think it all depends because every position works different for each female. Whatever the position is, rubbing her clitoris should do the trick.
have your partner get on her knees and put her head down on the bed. It puts her in a position that allows your penis to better hit the G spot. But why would you want a "fast" one? No woman wants a fast one.