How can I get a longer foreskin?

I sometimes have that problem too, it annoying hey! To overcome it, when washing it in the shower, i fully retract it, then usually stretch it and pull it right over my head. I find it works as long as i don't touch it for the rest of the day, but if i just randomly retract it (especially when erect) and pull it back again, it never goes all the way back over the head. Give the shower a go.