Deborah Heiligman said this quote

There were still few rules at Down House, and Charles was not very good at enforcing the ones he and Emma did make. This was well known among his children. In 1855, when Lenny was about five, Charles walked in to find his son jumping up and down and tumbling all over a new sofa.'Oh Lenny, Lenny,' Charles said. 'You know it is against all rules.''Then,' Lenny said to his papa, 'I think you'd better go out of the room.'And so Charles did.