Not too early. I sleep in Sundays.
3 seconds sound clip from the Back to the Future movie soundboard.
You can hear this line at 00:39:34 in the Blu-ray version of the movie.
Quote context
[...]
- Now, of course not, Biff. No. I wouldn't want that to happen.
- What are you looking at, butthead? (2)
- Biff, get a load of this guy's life preserver. Dork thinks he's going to drown.
- How about my homework, McFly?
- Not too early. I sleep in Sundays.
- Oh, McFly, your shoe's untied!
- Don't be so gullible, McFly. Okay.
- I don't want to see you in here again. Okay.
- What?
[...]