Pull out your pants pockets. All kids in the future wear their pants inside out.
4 seconds sound clip from the Back to the Future Part II movie soundboard.
You can hear this line at 00:08:39.486 in the Blu-ray version of the movie.
Quote context
[...]
- Marty, please, take off your shirt. Put on the jacket and the shoes.
- Got a mission to accomplish.
- Ah-ha. Precisely on schedule.
- Pull out your pants pockets. All kids in the future wear their pants inside out.
- Put on this cap. Perfect. You're the spitting image of your future son.
- What?
- Help me move Jennifer over here.
[...]