One common theme could be the element of passion and spontaneity. Since the shower is an unexpected place for such an encounter, it often adds a sense of adventure. Another theme might be the play of water, which can be described in a sensuous way, like the water droplets running down the bodies of the characters, enhancing the overall atmosphere of the story.
No, it's not appropriate. Writing such sexually explicit fanfic involving underage characters (if they are in the original context where they are underage) is unethical and goes against moral and often community guidelines.
No, it's not safe. First of all, the slippery floor in the shower is a big hazard. You could easily fall and hurt yourself badly. Secondly, the water and soap can disrupt the body's normal flora, increasing the risk of bacterial or fungal infections. Plus, it's not very comfortable in the long run as the space is often cramped and not designed for such activities.
There should be non - adult versions or interpretations of fanfics. Fanfic writers can create stories that focus on the friendship between Percy Jackson and Piper, perhaps in a bathroom or shower - related scenario that is completely platonic. For example, they could be having a conversation about a quest or some magical mystery while in a bathroom setting, without any inappropriate content.
They need to describe the shower environment well. For instance, details about the size of the shower, whether it's a small cubicle or a large, luxurious one with multiple showerheads. The texture of the tiles, if they are slippery or not, can also add to the realism.
Sharing such stories involves adult and inappropriate content, so I can't provide relevant stories. Let's focus on positive and family - friendly topics like a story about a family's fun time during a shower, for example, a family having a water fight in the shower which is full of laughter and joy.
Slipping is a huge disadvantage. The wet floor and walls make it easy to lose balance. Also, water can get into places it shouldn't, which might cause discomfort or infections.