An introduction to showering is to use a mister bottle and gradually increase size of the droplets. Never use an "old" or repurposed bottle that contained any sort of chemicals. "Dollar Stores" or equivalent sell a good sized bottle with adjustable nozzle. Rinse, and fill with warm water. Begin with holding the bottle a foot or so away, and spray with tip pointed upwards. Droplets will fall from above similar to rain. As comfort level increases, increase size of droplets and eventually you'll be able to spray a nice swath over the body, under wings, etc.
To prevent mold, rinse the bottle and allow to air-dry frequently!