I had been with my GF at the time for about a year. She had organized a trip to the beach with her four closest friends and another guy from school. We all stayed in the same apartment which had no rooms, it was just kinda separated in two sections, the front and the back (this will be relevant later) kinda like U shaped room. With one bathroom in the middle, no door.
We were going for three nights.
First night – While we all were getting ready, we all took showers in the only bathroom, I was in first, and my GF decided to join. We fucked in the shower, nothing special but she moaned enough that one of her friends cheered her near her climax. After we go out, her friend J [F] got in and took a shower (took about 20 min) but I didn’t make anything out of it.