The main characters are obviously Kakashi and Naruto. Kakashi is the experienced and somewhat mysterious ninja who has a lot to teach. Naruto is the eager - to - learn protagonist who is always looking to improve his skills.
Well, in some 'kakashi teaches naruto fanfiction', there might be a plotline where Kakashi teaches Naruto how to better control his chakra. This could involve some really intense training sessions deep in the forest. Also, Kakashi could be teaching Naruto about the art of stealth and infiltration, skills that Naruto doesn't have much experience with but are crucial for a ninja.
Naruto might be initially excited. He's always eager to learn new and powerful jutsu, and the Chidori is a very cool and strong one. He probably can't wait to start training and show off to his friends once he masters it.
Naruto's fighting style could become more versatile. He already has a wide range of skills, and adding the Chidori gives him another option. He can now combine it with his shadow clones. For example, he could send clones to distract the enemy while he sneaks in with the Chidori.
Well, there could be. Fanfiction writers love to explore unique and unexpected relationships. Since Naruto and Kakashi are both popular characters in the Naruto universe, some writers might come up with such a plot for the sake of creativity and exploring different storylines. But it's not a part of the official Naruto story.
Sasuke could be a popular character. He might be involved in the story in a way that either helps or hinders the situation where Naruto hurts Kakashi. For example, if Sasuke tries to stop Naruto from doing something stupid that would hurt Kakashi.
Another reason could be related to Kakashi's past actions. If there are some secrets or things Kakashi did in the past that come to light and Naruto doesn't like them, he could snap at Kakashi. Naruto has a strong sense of justice and loyalty, so if he feels betrayed or misled by Kakashi, his reaction could be to snap.
Sakura could be the one teaching him. She's known for being intelligent and having good domestic skills. She might start by showing Naruto the basics in the kitchen, like how to hold a knife properly and how to chop vegetables evenly.
It could be an old hermit who has been living in seclusion for years. This hermit has mastered the Goken and sees potential in Naruto. So, he decides to teach Naruto this powerful technique.
Kakashi might be initially surprised. But then, he would probably use it as a teaching moment for Naruto. He could say something like 'Naruto, stealing is not the way of a ninja.' And then give him a punishment like extra training.