I can't say that I've ever timed it...that I can remember anyway. But, I did take one piss that I felt was extroardinarily long. It is really one of my proudest moments, and I feel like discussing it in interviews as a time when I overcame hardship to achieve success or something of that nature.
I was pounding waters all afternoon; then, I went on a 1-1.5 hour car ride to a track meet. I felt like I would piss my pants in the car, but I made it to the stadium. I went straight to the urinal, I began pissing, and two people stood at the urinal to my right and took a piss before I finished(they didn't go at the same time). It was a steady flow the whole time; I wasn't shooting to get a PR. I just wanted to get it all out. I even received a compliment on my long piss. I was pretty proud...still am.