Actually, you might want to. There is a signifigant endorphin release from such an action, and there is a curiousness to the whole thing, just like massaging a sore muscle, where your inciting a response other than the standard type of operating. (For the massage analogy, I mean that muscles are meant to tense up, and massaging them is going the opposite, squishing them all out).

Now, I don't know anything about women because I rarely interact with them, but I have heard that for vaginal orgasms in women, there is a distinct feeling of needing to pee, due to swelling and diaphragm contraction. The advice that I've heard again and again for women having difficulty achieving orgasm is: Go pee before sex, get completely empty, and then let yourself succumb to the need-to-pee feeling during the act, and it'll all work out. (and you won't end up peeing everywhere). I bring this up just as a comparison that maybe the feelings of egestion are exactly what you want/what are linked to orgasmic function.

But I think there is a lot of caution and prep required. Sufficient hydration, so the colon isn't too sensitive. Sufficient relaxation, so the sphincter doesn't get hurt. Sufficient cleanliness, since feces isn't a good lube, nor do it play well with lubes. Stuff like that.