Cut the fur under the stumach but stop where the ribs are, and cut around his ''pee-pee'', but beware not to cut the dog cause they really get scared when you cut the skin my accident.
Also you can cut inside the legs.
I take Fido and wash him just with water about every 3-4 days on his stumach and legs if he pees himself much
Also keep the hair on his ''pee-pee'' long ! it helps with this proplem, less pee that goes on the fur then