The old lord is taking a bath, assisted by his old valet (his former batman).
V.: "may I draw your lordship's attention to the fact that his lordship has a hard one?"
L., looking down: "Indeed, John, you're right! What a pleasant surprise!"
V.: "Does your lordship want me to inform her ladyship?"
L: "Oh no, John, not at all; we'll try to smuggle him into town."