"How did you know I was thinking of anything?"
"Your face. It tells tales."
"Only nice ones to you, my dear lady."
"Ah, but you didn't tell—"
"Would you like me to?"
"Not if it's naughty. Your face looks naughty."
He wheeled, delighted. "Now, how does my face look when it's naughty?"
"Oh, that would be telling. It's just as well you shouldn't know."
"Was it as naughty as all that then?"
"Yes. Or as nice."