One common trope is the forbidden love between a human and a supernatural being, like a vampire. Another could be the power dynamics in sexual relationships within the supernatural world, such as an alpha werewolf and his mate. Also, the idea of soulmates in a supernatural context often features in these fanfics.
One of the main ethical concerns is the objectification of characters. It reduces them to sexual objects rather than complex individuals. This goes against the principles of respecting the integrity of fictional characters and can also be offensive to many fans who view the source material in a different, more positive light.
First, create interesting supernatural characters with unique powers and personalities. Then, build a believable supernatural world for them to exist in. When it comes to the sex part, make it consensual and integrate the supernatural elements in a natural way. For example, if one character is a shapeshifter, their ability could add an interesting dynamic to the sexual encounter.
Moderation is key. Fanfic platforms should have clear rules against such inappropriate content. They can enforce these rules by having a team of moderators who review submissions and remove any fanfics that violate the ethical guidelines.
In general, writing sexual fanfiction can be a bit of a grey area. When it comes to supernatural sex fanfiction, it may not be considered ethical as it often uses existing characters from popular shows or books in a sexual context that may not be in line with the original intention of the creators. Also, it can make some readers uncomfortable, especially younger ones who are fans of the original supernatural works.
One common theme is the forbidden love. For example, in many vampire - human relationship fanfictions, the sexual aspect is part of the allure of the forbidden. Another theme is the power dynamics. In werewolf pack stories, the alpha's sexual relationships can show power and hierarchy within the pack.
One could also look at some of the tales in Scandinavian mythology. There are stories of gods and magical creatures interacting in ways that might involve elements that could be related to the idea of'supernatural sex'. But these are often told in a more veiled or symbolic way compared to modern interpretations.
I'm not really into promoting or discussing fanfiction with sexual content as it may not be suitable for all audiences. However, in general, for non - sexual supernatural fanfiction, there are many great ones about vampires, werewolves, and witches. For example, some focus on the complex relationships between characters in shows like 'Supernatural' in a non - sexual way.
There are some indie or niche publications that might explore such themes. But they are not as well - known as mainstream literature. For example, in some small - press anthologies of queer speculative fiction, there might be stories that include gay relationships within a supernatural setting, but they are not easy to come by and often not promoted widely.