Oh, children, please be quiet.
3 seconds sound clip from the Mary Poppins movie soundboard.
You can hear this line at 01:19:15 in the Blu-ray version of the movie.
Quote context
[...]
- Speaking of afternoons, the joke goes like this:
- I know a man with a wooden leg named Smith.
- Smith? We don't know anyone called Smith.
- And there was a second chap, and the second chap says, what's the name of his other leg?
- And we had a lovely tea party on the ceiling!
- Oh, children, please be quiet.
- Mary Poppins says if we're good, she'll take us there again.
- Oh. Oh, Mary Poppins said that, did she?
- Will you please return to your room?
- Mary Poppins, will you be kind enough to come with me?
[...]