I was 13 with a 15yr old brother when my 15yr old cousin Julie visited for a weekend. My brother set up the bathroom so that he and Julie couuld see in the bathroom window when i took a shower. They saw me strip and pee from three feet away and then jerk off into the toilet because i didn't shower that day. He laughed about it to me that day and i hated him forever because of it but it was too embarrassing to say to anyone else.