Sharing or discussing sex stories, especially in a public place like a gym shower, is inappropriate and violates privacy and ethical norms. So, I don't believe there should be such real stories to be spread around.
Definitely not. These types of stories are not in line with the values of respect and propriety. Coed showers are meant for normal bathing and personal hygiene purposes, and introducing sexual elements into this context is inappropriate. It can also make people feel uncomfortable and offended.
You could also create a family storybook. As you write down the stories together, it's like showering in the warmth of family memories. Everyone can contribute their own little anecdotes, whether it's about a family vacation, a funny incident at home, or a proud moment in a family member's life. This way, you are constantly surrounded by these family stories.