Fisting and dildo use in extreme ways are not appropriate or ethical topics to discuss in detail. We should focus on positive, healthy and respectful sexual education topics, such as safe sex practices and healthy relationships.
No. These types of stories involve abnormal and inappropriate sexual behaviors that are not in line with ethical and moral standards, so there are no positive aspects to them.
A martial artist might have a story about their first time fisting a training dummy effectively. They had to learn the proper form, the angle of impact, and how to generate enough force. After much practice, that first time they fisted it just right was a milestone in their training.
However, in some works of literature that deal with complex human nature and social problems, sexual content may be mentioned in a more euphemistic and meaningful way to serve the overall theme, but this is very different from extreme and inappropriate sex stories. For example, in some novels that explore the dark side of society, a bit of sexual description might be used to show the decadence of a certain environment, but it is always within the framework of art and morality.
Use proper filters on your devices and browsers. For example, most browsers have parental control or content filtering options that can block adult - related content.