It's highly unlikely that this fanfiction is popular. While there are all kinds of fanfictions out there exploring different aspects of the 'Twilight' universe, this one seems so far - fetched and against the normal perception of the characters that it would probably only attract a very small number of readers who are looking for extremely off - the - wall and unique takes on the story. It's not the kind of plot that would easily gain mass appeal among the 'Twilight' fandom.
I would doubt it. Given the rather odd nature of the idea of Carlisle changing Bella's diaper, it doesn't seem like the kind of fanfiction that would appeal to the general 'Twilight' fan base. Most fans are more interested in the romantic, vampire - related aspects of the original story, not such a bizarre situation.
I'm not sure specifically as this sounds like a very strange and perhaps non - canon fanfiction concept. It could be some sort of very odd - humor or AU (alternate universe) take on the 'Twilight' characters where Carlisle is in a situation where he has to change Bella's diaper, perhaps in a scenario where Bella has been de - aged or something equally outlandish.
One common theme is the family dynamic. Carlisle being the patriarch, his influence on Edward and Bella's relationship within the family framework is often explored. For example, in many fanfictions, he helps them navigate the difficulties of being part of a vampire family.
Another common theme is the idea of Bella's transformation in a way that is influenced by Carlisle. This could be in terms of her values or her understanding of the vampire world. For example, in some fanfictions, Carlisle helps Bella to see the good in the vampire existence beyond just being with Edward. It's about her growth and how Carlisle plays a part in it.
One great fanfiction could be 'Carlisle's Influence on Bella'. In this, Carlisle might change Bella's perspective on life as a vampire. He could teach her about the history and culture of vampires in a way that enriches her understanding. Another could be 'Bella's Transformation by Carlisle' which focuses on how Carlisle's medical knowledge and his gentle nature impact Bella during her transformation process.
It could be because it offers a new perspective on their relationship. In the original story, Carlisle is more of a father figure, but in fanfiction, this dominant role can bring out different aspects of their personalities and create more exciting storylines.
Often, it starts with an unexpected encounter or a moment of realization. Maybe Carlisle sees Bella in a new light, not just as Edward's girlfriend but as an individual with her own charm. Then, there are small gestures of kindness and understanding between them that gradually build up the relationship.
You can start by looking on fanfiction.net. It has a vast collection of Twilight - related fanfictions, and there's a high chance you'll find some good ones about Carlisle changing Bella there.
One possibility in such a fanfiction could be that their relationship completely alters the dynamics of the original Twilight story. For example, it might change how the Cullen family functions and their interactions with other characters. Maybe Bella's connection with Carlisle would lead to a different approach in dealing with the Volturi.
There is also 'Carlisle's Care'. This story might focus on Carlisle's role as a doctor not just in treating physical ailments but also in helping Bella deal with the emotional and psychological impacts of being part of the vampire world. He could use his medical expertise to ease her transition and make her understand her new reality better.
Well, 'Carlisle's Forbidden Kiss' is also quite well - known. It shows a scenario where Carlisle struggles with his feelings for Bella due to his moral code. The kiss in this fanfiction is a very emotional and intense moment that makes the whole story gripping.