I have about 1/2" overhang when I'm soft. When I was a teenager, my foreskin wouldn't retract much at all when I got hard, but the doctor I saw at the time told me to slide the skin back as far as it would go without hurting when I masturbated. (There was some quite a bit of blushing on my part, especially since the discussion assumed--correctly--that I was masturbating regularly.) Within a few months I could slide my foreskin all the way back without any discomfort. As others have noted, ther's no such thing as too much foreskin!