Is it safe to put your shower hose is your anus and turn it on?
Doing that -- what some people humorously call the "bum's rush" -- is a bad idea. The membranes of the colon are pretty fragile. It only takes 2-3 pounds of pressure to rupture the colon. If you wish to experience that -- many people do because it can cause sexual arousal -- buy some enemas at the drug store. An enema is a pre-mixed water/soap solution in a soft plastic bottle, and it has a long soft tip to insert into your anus. If you do it for fun, don't make a habit out of it, because it will change your normal bowel-movement schedule.