He takes 20 to 30 minutes.
5 seconds sound clip from the Fast Times at Ridgemont High movie soundboard.
You can hear this line at 00:59:24 in the Blu-ray version of the movie.
Quote context
[...]
- I gotta go, Stacy. I've really gotta go.
- See ya.
- Bye.
- I thought you said he took 30 to 40 minutes.
- That's right. I'm sorry. I meant 30 to 40 minutes.
- Why? How long did Damone take?
- Damone took 15 to 20 minutes.
- That's not bad for a high school boy.
[...]