It depends on how it's written and who the intended audience is. If it contains excessive or inappropriate content, then it may not be appropriate. However, if it's written in a more light - hearted or satirical way, it could be considered acceptable within certain fan communities.
I'm not entirely sure specifically as 'fanfic' can vary greatly. It might be a fan - created fictional work related to the 'Being Human' series that involves the concept of spanking in some way, perhaps in a disciplinary or comical context within the story's world.
One idea could be exploring what would happen if the main characters had to face a new supernatural threat that was a combination of different mythical creatures. For example, a werewolf - vampire hybrid that was immune to the usual ways of killing them.
Fanfiction.net is also a place where you might find 'being human gay fanfic'. However, the search function there might not be as refined as AO3. But it still has a wide range of fan - created stories that could include what you're looking for. Just be prepared to sift through a lot of results.
There are 'being human gay fanfic' that take the concept of the show's supernatural elements and combine them with the gay relationship aspect. For instance, a fanfic could have a vampire and a werewolf in a gay relationship, and how they deal with their different natures while being in love. It could be an interesting take on both the genre of supernatural and gay relationships.
First, re - watch some episodes to get a good feel for the characters' personalities and the overall tone of the show. Then, pick a starting point. It could be a small moment from the show that you want to expand on, like a conversation between two characters that you think could have led to something more interesting. Just start writing down your thoughts and ideas, don't worry too much about grammar or making it perfect at the start.
The fanfic might focus on the relationship between Aidan and Sally. It could explore how they support each other in their struggles to be something close to normal humans. For example, Sally could be learning how to interact with the living world better with Aidan's help, and Aidan could be relying on Sally's unique perspective as a ghost-turned -almost -human.
Aidan is a complex character. He has a long history as a vampire and has seen many things. Sally, on the other hand, was a regular person before she died and became a ghost. In the fanfic, they are likely to be the central focus, with their personalities and abilities driving the story. Their different natures - one a vampire and one a former ghost - bring a lot of interesting dynamics to the story.
It's not common. The Pokemon franchise mainly revolves around things like collecting Pokemon, training them for battles, and exploring the Pokemon world. A human being pregnant with a Pokemon is something that really goes against the traditional ideas in the Pokemon series. However, in the world of fanfic, some writers might use this concept to create very creative and thought - provoking stories that can attract readers who are looking for something different and edgy.