It is important to understand the causes of shy bladder.
This syndrome can only be overcome with understanding.
There is no magic pill that can be swallowed, only a reorientation in the way you think and the way you deal with your fears. That is only possible if you truly know what it is you are dealing with.
While knowledge and understanding alone will not overcome shy bladder or paruresis - you will need to take action to overcome your fears - this is the first and necessary plank to success.
A negative experience in a public toilet in the past plants the idea in your mind that you cannot urinate in public toilets. So when you go to urinate in public you expect that you will not be able to do so. Naturally in that case you cannot go and this reinforces the belief even further.
After many many cycles like this the idea that you cannot urinate in public becomes so strong that unless you actively take steps to break the cycle the self fulfilling prophecy goes on forever.
This is the root issue behind shy bladder. There is no biological reason why you cannot urinate in public, it is purely psychological and based on an idea formulated in your own mind.
Often this self fulfilling prophecy starts with an early negative experience. i have been trying to rack my brains to work out where my shy bladder started. I remember being able to urinate in public as a child. But I also remember a situation where I was at the urinal and a kid who was circumcised looked at my penis (not circumcised) and says, "yours is different to mine!"
I must have been about nine or ten years old. I can't remember it affecting me at the time but after suffering mild shy bladder in my teens and early adulthood I figure that it must have been this event that triggered it.
But what you need to understand is that the fear is entirely irrational. Of course circumcised and uncircumcised are going to look different. There is no logical reason why that should make one afraid to urinate in public. But that's what irrational fears do. I became afraid to do private business in public in case anybody told me I was different.
It is a primal fight or flight instinct that is triggered. We are biologically hardwired to stop urinating in a fight or flight situation. In the wild if something threatening crept up on us while we were doing our business the body would stop the process in order to allow us to fight or run away.
If an incident or experience develops the fear of urinating in public then every time we step up to do our business we feel under threat. This feeling of being under threat triggers the fight or flight response and our body won't urinate.
Understanding these causes allows you to then work to overcome them. It is possible to reprogram your subconscious and break the cycle of a self fulfilling prophecy. You can work to get yourself in a situation where you do not find a public toilet a threatening environment. Then you will be able to relieve yourself at will. It all comes down to understanding.