I don`t think I have ever experienced a pure-anal orgasm - I need additional stimulation, preferably clitoral. Oh and if the vagina is involved as well... everything at once... God. Anyway: when I orgasm during anal sex, my anus contracts and grips like anything, I can really feel the contractions far more than with a vaginal orgasm. It`s scarey and divine at the same time; very intense; but yes, I agree that it is for whatever reason just not enough: still need to get that pussy seen to!