Win said: "Because of the seeming requirement that one has to have a relatovely full colon and NOT had a enema for a while, I only achieve it a few times a year these days - but when it happens, OH MY ! "
I absolutely agree about the "oh my" part. The sensation of powerful directional contractions, especially when they originate at the cecum, is simply delightful. Difficult to describe delightful. Addictively delightful.
But I disagree that one has to be full of backed-up poop to enjoy the experience. Recently I have been routinely enjoying powerful whole-colon expulsive sensations, waves of contraction that feel like they begin at my ileo-cecal valve and travel in a sweeping wave to my anus. The wave of contraction will expell everything in the colon if allowed, but the pleasurable wave will also writhe against a stretched full colon of retained water.
So here I go off again about my chilled-water enemas. All I'll say is that properly done, a two liter slow-drip enema of refrigerator-cold water into my empty colon, retained with a tampon, will induce writhing colonic contractions virtually every time. If the mood and mindset are right, they will quickly involve my uterus, and the subsequent whole-body writhing in pleasure messes up the bed. (Don't forget the tampon or the bed will get messed up a different way!)
It simply is an orgasmic experience that frankly far surpasses any partner or solo sex session I've had any other way. Try it, you'll like it.