Welcome! Sometimes, it is easier for someone with some "distance" to do a bit of searching. I think if you can connect up with some other folks dealing with MS, you will receive - and eventually share - tips to help. Just as we do here on PT for more general things.

One place I looked at suggested keeping the area around the private parts a bit shaved to help with washing, cleaning and avoiding developing a rash. YOu need to tap in to a group of folks for tips like that!