I couldn't jizz from sex until I was 17 because I had comfort and trust issues. 3 years of uncomfortable and awkward condom sex. Then finally went bareback with the girl I was with from 16-17 and each session ended with nothing but a red rocket and both very worn out.
Then one night I was in her room on campus and watching The Emperors New Groove, and we started going at it. Flipped her over etc. About half an hour later I finally was able to. She was like "Did you just..." "Errr, yeah" then she literally jumped up, stuck her undies and a hoodie on and went running to her best friend who was a few doors down and was yelling and screaming with joy.
Obviously I'm just turned on by animated llamas.
Nowadays it's as early as I don't want it to be (focus, focus focus DISTRACT YOURSELF OH GOD THINK OF DEAD PUPPIES there we go, ok focus focus) or as long as I want it to be provided I've already jacked off that day.