once a man has had his orgasm his interest in further sex plummets. Now I don't know if the same is true for women but I suspect that it is.
Obviously, I can't speak for all women but I will give you my experience on the matter. My H always goes the same route too...I get my orgasm first through oral or manual, then we go to the actual "act".
Well, by that time, I am usually exhausted (orgasms make me want to go to sleep!) and half the time, dried up. Neither make for the world's best nookie, if you know what I mean. There have been times when I have tried to get H to stop before I have my orgasm so that I can channel that energy into mind-blowing nookie for him, but he is so intent on my orgasm that he doesn't want to stop.
