Our society promotes moral and ethical values, and topics related to sexual activities in inappropriate settings like this are not acceptable for general discussion.
No. Such content often involves inappropriate and vulgar themes which are not suitable for public or general creation. It goes against moral and ethical norms in most societies.
There are many great underwater adventure stories. For example, Jacques Cousteau's exploration of the deep sea. His team used advanced diving equipment to discover amazing underwater landscapes, unknown species, and ancient shipwrecks. It was a journey full of surprises and knowledge - gaining.
The term'sex' in this context is likely to lead to inappropriate implications. However, there could be stories about underwater life'sex' (in the sense of male and female organisms), like how some fish species reproduce underwater. For example, seahorses, where the male seahorse is the one that gets pregnant. It's a unique and fascinating underwater reproduction story.
It is highly inappropriate. Fanfiction is often read by a wide range of audiences, including minors. Content that involves sexual themes, especially those as specific as 'underwater breathholding sex', is not suitable for public consumption and violates the general norms of decency.
It promotes an inappropriate and vulgar culture. Such content is not suitable for public consumption and can have a negative influence on the mental health of those who are exposed to it.