Let’s start with colonic cleansing.
Beyond the basic “ew” factor of having a hose inserted into your bottom and then be flooded with liquids “designed to flush out impurities,” there’s nothing to this.
The part of the body that is being “cleansed” is already doing the cleansing.
When you have a bowel movement, you are evacuating the waste from your bodily functions.
And having anything physically inserted into the rectum risks perforating the intestine… leaving your gut exposed to a host of dangerous infections.
Better to skip it and let the bowels just do their job.