The other two nuns disapprove, and ask, "What if someone sees us?"But the Mother Superior says, "Don't worry, no one will see us, we'll just lock the door."
So the other nuns agree, strip down and return to work.
Suddenly, they hear a knock at the door, and grab their clothes in a panic.
Mother Superior runs to the door and calls through, "Who is it?""Blind man," a man's voice comes back.
So she opens the door, and lets in the blind man, who turns to the nuns and says, "Great tits, ladies, now where do you want these blinds?"