The best way to do sanitary trim is to use a clipper. They have tiny ones you can use for their private areas & their paws. If she wiggles a lot, I wouldn't use a scissor unless it has a blunt end.
Please wash her indoors in a sink...you can always wear a glove if it grosses you out.
You don't want to scare her w/the garden hose & cold water while you're washing her, she'll wiggle more & make grooming time just so much more difficult.