Based on your description, it seems that the most to worry about with the piercing is an infection. But this would present with a skin reaction, redness at the least and it seems you never had this problem. It would be best to have yourself examined by the doctor to make sure the piercing does not compromise any of the tubes and tubules.
Are you talking about discharge from the urethra? Or from the piercing site? There could be some fluid that may leak out from the piercing site, light yellow, clear, not milky though. Again, let me reiterate the importance of a physical examination.
The discharge is from the urethra. Is it possible that any infection from within the scrotum sac... may cause side effects such as this?