Buttonhole circumcision 

A slit in the dorsal surface of the foreskin that the head of the penis is pushed through. Technically it is a piercing and not circumcision because the cut is not all the way around, and no tissue is removed. Healing is faster than after regular circumcision because if an erection occurs it helps keep the wound closed, rather than splitting stitches. No sensitive nerve rich tissue is lost, and the head does not dry and loose sensitivity due to a process called keratinisation because it can still be covered by the foreskin after healing is complete. Foreplay and masturbation are greatly enhanced and the foreskin ads extra stimulation for the woman during intercourse, kind of like a ribbed and textured sex toy.

This guy had the weirdest cock I ever seen, looked like it was cut, but there was this flap hanging down under the head. He said it was called a buttonhole circumcision.

Buttonhole circumcision by Buttonhole man September 9, 2010