You need to use special soap that has the right pH value. Handsoap / shower gel is not the correct one.

please use more than just water.

Unless you have a vagina, in which case err on the side of no soap, unless it becomes a problem (and then buy special soap)

Ha, I do use soap. I just heard somewhere you aren't supposed to use any.

Not regularly but before / after intercourses. And for the ass usually after each time you need to defecate.