Buck's sister, a maiden lady of uncertain years, was on hand to play chaperone.

I shall have to look after you and play chaperone!

As a rule, his aides saw no need to police him and had no desire to play chaperone.

Lunch right there in the middle of town before God and everybody... although, with a New York lawyer to play chaperone, what harm in that?

Hermione guessed that Gaspare had been playing chaperone, and loved him for it.