So I am 21 and uncut. I can remember peeling back my foreskin when I was about 16 and there being some sticking of skin and pain followed by full retraction. OR, so I thought.
About a month ago I was receiving a handjob when I felt a sharp twang of pain, then the same pain again. On closer inspection it would appear that I had torn a small hole at the front of my frenulum. It was at this time that I decided to investigate further and became aware that my penis wasn't entirely normal.
As you can see when I pull my foreskin back the frenulum is pulling the head forwards, and there is also a tight band of skin that extends from the base of the frenulum around the penis - which when erect sits very tightly just below the head if I want to pull my foreskin back (I haven't been doing this while having sex, rather just leaving my foreskin to cover the rest.
Editor Note: Note the raphae (the red squiggly line is visible running down the back of the penis in the 4th pic)