Hi, im 18, i have never been able to pull the foreskin back more than about 5mm, this is because it is covering most of the head also if i try pulling back more than this there is a small piece of string type thing connected to the head and the foreskin stopping it from going back further. This isnt a problem personally but is it an actual problem? for example in porn movies the head of the penis is always out and im not sure what is normal as ive never asked. Please help