With a strikerfired pistol and a kydex holster, there's a 0% chance it goes off while in the holster. There are zero reports of that ever occuring. The only way it would happen is if you intentionally took out the gun and pulled the trigger. It's 100% user error and 0% hardware/holster error. The gun comes out with the holster when you take it off your person at the end of the day or when putting it on in the morning, this eliminates any chance of it going off.

If you are feeling confident in your trigger disipline then you can start pulling it and shooting at the range for practice, which will add some percentage of ND occuring, which may be .00001% depending on your skills and the speed at which you do it, but we take riskier chances in our every day lives that have much greater chances of death, like driving, or even eating food(choking hazard).

Be confident in your abilities, train yourself untill you get burned out on it, and then push youself even more, do it with passion, engrain it into your brain, the finger does not go into the trigger guard until you are on target. When you get to the point of enlightenment you can yell out at the top of your lungs I HAVE A GUN POINTED AT MY DICK!!! and know with confidence that your dick is safe, tucked away snugly.