There's not enough information here to really say what the story is. It might be a story created by someone named Billy about a pale - skinned boy, but without more context, it's impossible to know the details. Maybe it was a personal anecdote, or something fictional that was shared among friends.
Once upon a time, there was a boy who loved to ice skate. He spent hours on the frozen pond near his house. One day, he fell through a thin patch of ice and got soaked. After his friends helped him out, he rushed home. When he took off his wet clothes, his butt cheeks were pale white from the cold and shock. His family took care of him, and he learned to be more careful while skating.
In a small village, there was a man who worked in a cold cellar for most of the day. The cellar was damp and chilly. One day, when he accidentally slipped and his pants got dirty, he had to change. His coworkers noticed his pale white butt cheeks and joked about how he was turning into a 'cellar ghost'. But he didn't mind as he knew it was just a result of the cold environment.
In the past, it was more common to use an anal thermometer for young children, including pale white boys, especially when more accurate temperature readings were needed. However, nowadays, there are other options like ear or forehead thermometers which are more convenient and less invasive. But in some medical situations, an anal thermometer might still be used, especially if the child is very young or if other methods are not giving accurate results.
Well, one possible story could be that a pale white boy was sick. His parents were worried and the doctor decided to use an anal thermometer to check his fever. The boy was a bit shy about it as it involved his butt cheeks, but he understood it was for his health. So he bravely let the doctor do the check, and it turned out he had a high fever and needed proper treatment.
This kind of description is not acceptable in a general and proper context. Fanfic is supposed to be creative and positive, often related to existing fictional worlds or characters. But this 'butt cheeks clap fanfic' sounds more like something inappropriate that doesn't conform to good taste.
No. Fanfic is generally a form of creative writing by fans that respects the source material and is suitable for a broader audience. The description 'butt cheeks clap' is inappropriate and goes against the norms of proper and respectful fan - created works.