I have been doing air enemas for over 15 years and enjoy the feeling of complete fullness. To get the same effect with water requires a colon tube long enough to penetrate the small intestine. It is not a good idea to force enema from the colon into the small intestine so by using a long colon tube you get clean water. The problem with water is that if you take too much you will throw up and that is very unpleasant. Air is much easier and the only requirement is to be cleaned out and it is very important that all water is expelled first to avoid cramps.
My air enema regiment starts with a large single inflatable silicone balloon tip enema nozzle fitted with a check valve that fits the air line from the aquarium pump and an adjustable flow Optima aquarium air pump.
Once connected, I start the air flow on max flow until a cramp sets in, then reduce or stop, then restart the flow as needed while massaging the abdomen until I feel the need to belch. At that time I continue the flow for approximately 15 more seconds then stop the flow and hold the belch for a few minutes, then let it out (the first filling usually takes 15 to 30 minutes). I never rush it and stop at the first sign of pain. When properly filled I only feel fullness, no cramps or pain.
If I have the time I will repeat this for several hours and each time the intestines hold a little more air before the need to belch.
This complete intestinal fullness, while holding the belch, along with a full bladder will enhance orgasm beyond imagination.
Warning; always stop the air flow before orgasm or you could overinflate!
A word of caution, if it hurts, stop. Play safe, pay attention, and don’t exceed your limits. Never use anything except an aquarium air pump or something that you can manually control for obvious reasons.