However, the summer I was 22 I was out backpacking through Europe for a month. On the evening before the last day of the trip I was at "Gare du Nord" in Paris and was going to take the night train to Copenhagen.
While waiting to board the train, I felt an insistent need to relieve myself and knew I wouldn't be able to wait until I got on the train, so I went looking for a restroom.
I soon found a huge "Gentlemen's" in the cellar of the railway station. The first part of the room consisted of two lines of 15 urinals on the opposing walls. Almost all the slots were filled, except one almost at the end to the right, so I went there and started doing my business.
Just as I had started, I felt a nudge on my right shoulder from the man standing next to me. I looked at him, wondering what he wanted. He looked me in the eyes, then looked downwards. As I followed his gaze I saw that he was masturbating. Not only that, but all the other occupants were also erect and playing with themselves and looking towards me. Not only that, but as I looked over my shoulder I noticed that the row of men behind us were also jacking off and looking at me.
To this day I'm not sure why, but my external urethral sphincter - which supposedly controls the voluntary peeing - immediately cramped shut and my body started shaking as I felt more than 25 men looking lustfully at me.