Well, orgasm's not an entirely genital event. A lot--if not most--of orgasm takes place in the brain.
In addition, who's to say a woman can't receive stimulation of the clitoris, G-spot, or whatever while having anal sex? Food for thought.
Kissing girls in English at the back of the stairs, you're a honey with a following of innocent boys, they never know it because you never show it..." - Belle and Sebastian