someone who usually keeps to themselves and is unpopular or a loser. The "leather jacket foreskin" is king of the foreskins and is therefore a much bigger loser than the rest of his foreskin crew. Usually people with the name "dylan Bretherton" are reffered to as leather jacket foreskins because they are bullied by their peers.
guy 1: hey did you see dylan at the party
guy 2: no. he never goes to parties
guy 1: hes such a leather jacket foreskin
guy 2: i heard he got bummed by taylor nastri