i cant pee when someone is urinating next to me.
I used to have that problem when I was a kid. I got over it.
When there's a dude next to me at the urinals in a public restroom who is obviously uncomfortable, I talk to them just to be friendly and to throw them for a loop. I might say something like, "It's a bitch when you have to pee and can't, isn't it?" Ha, ha.
Most guys are so uptight in public restrooms, that it is just funny. Most women, on the other hand, feel free to chat it up with other women while peeing or whatever.