You write it, and I'll tell you what I want to say.
5 seconds sound clip from the A Charlie Brown Christmas movie soundboard.
You can hear this line at 00:07:44 in the Blu-ray version of the movie.
Quote context
[...]
- Lights-and-display contest? Oh, no.
- My own dog gone commercial. I can't stand it. Oh.
- I've been looking for you, big brother.
- Will you please write a letter to Santa Claus for me?
- You write it, and I'll tell you what I want to say.
- Dear Santa Claus, how have you been? Did you have a nice summer? How is your wife?
- I have been extra good this year, so I have a long list of presents that I want.
- Please note the size and color of each item and send as many as possible.
[...]