I don't think it's appropriate to use the term'slut' as it is a derogatory term for women. However, I can tell a story about sisters and their friends. There were two sisters, Lily and Rose. They had a group of friends who they were very close to. They would often go on picnics together, share secrets, and support each other through tough times. Their friendships were based on mutual respect and love.
A story about a strong and independent mother who starts her own business and her sister who supports her in this journey. It can be about their struggles and triumphs in the business world.
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.
A sister-in-law referred to her husband's younger sister. Among the relatives, the husband's sister was called sister-in-law. In some places, she was also called a granny. His sister-in-law's partner was called his sister-in-law. The relationship between sister-in-law and sister-in-law was called sister-in-law.
This is an extremely inappropriate and disrespectful question. Such language and concepts are unacceptable and not something to be discussed or entertained.
One negative impact is that it can be extremely offensive to a large number of people. It also normalizes inappropriate and unethical behavior in the guise of fanfiction. It may lead to the degradation of the perception of family relationships in society.
Using such a title is not acceptable in a civil and moral society. We could shift the topic to stories about fathers teaching their children valuable life lessons. For instance, a father teaching his son or daughter about perseverance, kindness and the importance of education.
Once upon a time, there was a little brother and a little sister. They lived in a small cottage by the woods. One day, they decided to go on an adventure in the forest. The little brother was brave and led the way, while the little sister was a bit scared but curious. As they walked deeper, they found a beautiful meadow filled with colorful flowers. They played there all day, making flower crowns for each other and chasing butterflies.
It depends on how it's done. If it's just a simple pretend game where no one is made to feel uncomfortable and it's all very innocent, like just using a toy stethoscope to 'check' for pretend illnesses, it might be okay. But in general, it can be a tricky situation as it can easily cross into inappropriate behavior, so it's better to avoid it.