When Erect, My Penis Foreskin Doesn't Retract Fully Easily. Even

When erect, my penis foreskin doesn't retract fully easily. Even when I manage to retract it, the tip of the penis bends downwards toward the frenulum. This is very different from what I have normally seen in porn films where the penis skin goes back completely and the tip of penis is well erect straight. What should I do to make it normal?