I was playing with my arse when I was a boy who hadn't yet grown inhibitions.
I don't remember ever stimulating the prostate, but the anus itself can be a pleasant addition. I like to do that some times when I'm imagining fucking a female in the arse. Something about feeling both roles or thinking I know how she feels is enticing. I read advice for men or people having trouble getting aroused. One advice given was to feel imagine what your partner was feeling.
If you want to clean more deeply than immediately within, it takes a while.
There are plenty of wrong warnings about anal play, though there are some dangers also.
Real dangers:
- do not put a hose of water in the small intestine and use high water pressure. It can burst.
- If you use a hypertonic solution for rinsing, be careful with the concentration. It is possible to irritate your bowel/large intestine.
Wrong dangers (claimed dangerous but are not. Are safe entirely or somewhat):
- using tap water can kill you due to small organisms in the water.
- wine in the rectum is deadly. Be careful with salted cooking wine though.

The scope of my reply was greater than the question.
Could we change the subject of the thread to 'Anal Play'? Otherwise, we can start a new thread.