How do I tell my husband he needs to wipe and clean his ass better?

He gets poo stains on his bath towel daily. His boxers always have massive skid marks. His trousers smell of poo, and he even regularly smells of poo. Sometimes when he smells, I suggest he should take a shower, saying that he smells sweaty or something like that because I don't know how to tell him he smells of sh*t. I have commented on the stains on his towel, which he puts down to "vigorous wiping" -- but I see it as improper washing.

I am tired of doing his laundry because of the poo and I refuse to share towels under any circumstances. He suffers from anal itching and doesn't seem to realize that it could be because of his dirty bum. Help! What can I tell him?