While at school several years ago, I felt the need to rub one out in a bathroom stall on campus. While I was flailing away, I heard someone come in the bathroom and they selected the stall next to me. I thought they were taking care of their own business when the next thing I know, the dude in the next stall over had his head over the stall wall checking me out! What. The. Fuck. I was not amused.
Me: "What the fuck?"
Him: "Sorry! I thought you were someone else!"
He dipped back behind the wall and was out bathroom immediately.
My chubby was gone, so I went on with my day.