I could tell ya, but that's another tale for another day.
4 seconds sound clip from the Song of the South (1946) movie soundboard.
You can hear this line at 00:57:57.969 in the Blu-ray version of the movie.
Quote context
[...]
- So now, it's Brer Fox's turn to feel humble-come-tumble.
- But old Brer Bear, he don't say nothing.
- And Brer Fox, he lay low! Mighty low... sure enough.
- Tell us another one, Uncle Remus. The one you told daddy about Brer Frog havin' a tail...
- Well then, how can there be a tale...
- I could tell ya, but that's another tale for another day.
- Now you better run along and get that pup something to chew on besides my shoes.
- Pretty good, sure as your born.
- Just 'cause old Remus take your side don't mean we ain't gonna get Teenchy.
[...]