My midwife used to teach all expectant mothers to save a large washing up liquid bottle, prefarably one of the old fashioned tall opaque white ones, as they were taller and easier to hold and squeeze in the same hand, fill it with warm water with a teaspoon of salt added to aid healing, and sit on the toilet or stand in the bath and squirt themselves with that!
Using a garden spray bottle, the type with a hose and wand also makes for a convienient portable shower, just fill with warm water and whatever liquid soap or shower gel you fancy.
I have also seen purpose made bidet bowls, that are designed to fit inside a toilet bowl, for sale in some disability equipment catalogues, just fill up with warm water, use, and then
pull the plug out the base to empty when finished!