Different case studies of phimosis (a tight foreskin). Mostly taken from network54 phimosis forum. See right panel for link to my other blog about my theory of how masturbation can cause phimosis.
Editor Note: Contrary to current medical opinion I believe most adolescent phimosis is not caused by Lichen Sclerosus or Balanitis Xerotica Obliterans. Instead I think it is a consequence of applying too much pressure in masturbation which damages the 3 spongy chambers of the penis. See http://uktightforeskin.blogspot.co.uk/