I don't think it is appropriate. Such works usually contain elements that may be offensive or not suitable for general public consumption, and they may also promote negative values.
Well, first of all, it's a bad influence on the psychological development of readers. People, especially young people, may get wrong ideas about gender roles and sexual relationships from it. Secondly, it violates the basic moral bottom line of society, making the cultural environment more vulgar. Thirdly, it may also cause discomfort and harm to those who uphold positive values.
He could also be a character from a particular fictional universe that has been adapted or expanded upon in fanfiction. Writers might give him new abilities, relationships, or story arcs to explore different possibilities within the realm of the original story.
Once upon a time, there was a dancer named Lily. She had a big booty which was famous in her dance troupe. When she danced, her big booty added a special charm to her performance. People were attracted by her energetic moves and the unique rhythm created by her body shape. It became her signature feature and inspired many young dancers to embrace their own body features and be confident in themselves.
It might be a description of a person in a story where the focus is on their physical feature (the big booty) and their action of going to the motel. It could be a stranger who the storyteller witnessed going into the motel, and they decided to create a whole story around this one sighting.
Big Daddy in Bioshock fanfiction is typically portrayed as a large, lumbering but very protective figure. They are often associated with the Little Sisters. Big Sister, on the other hand, is usually more agile and aggressive. She has a more menacing presence compared to Big Daddy.
It's completely unethical. It goes against basic moral values. Family relationships should be respected, and creating such fanfiction with sexual or vulgar undertones related to family members is unacceptable in a civilized society.
There's no way to tell who created the 'big booty tube story' without more information. It could be an individual with a vivid imagination, or it might be the result of a group effort during a brainstorming session for a creative project.