My DS (20 months) has always had a slight bump on the side of his willy and his willy looks ever so slightly lop-sided. We've never thought too much about it, because his willy is little we thought it would just sort of straighten out as he grows.
But we've noticed he doesn't like it when we touch it if we need to wipe it when changing his nappy. If I need to lift his willy (when he's done an explosive poo!) he cries. Other than that he's absolutely fine, no problems with weeing, etc.
We can take him to the doctor later in the week but wondered if anyone has any ideas what it could be?