One thing to remember with "anal douches"/enemas is that your large intestine is where a lot of water is absorbed back out of the feces. This means that if you put any chemicals into that area, the body'll just schluck 'em in. DO NOT use alcohol! You can give yourself alcohol poisoning if it's absorbed via the other end of the digestive tract, because it's not making a slower journey from the stomach, through the system.

Or so I have heard. It is hearsay, I admit, and I welcome correction if I'm wrong. O:>