One possible analysis could be that their relationship in fanfic often showcases a strong bond of friendship. Bakugo's explosive personality and Kirishima's more stable and friendly nature create an interesting dynamic. Fanfic writers may explore how they support each other during battles or in their daily lives at school. For example, Kirishima might be the one to calm Bakugo down when he gets too riled up, and Bakugo could inspire Kirishima to be more confident in his abilities.
Such fanfics are inappropriate. Fanfiction should focus on positive aspects like friendship, adventure, or character development. Sexualizing characters in this way can create an uncomfortable and unwholesome environment within the fan community. It may also violate the terms of use of the platform where it is posted if it contains explicit content.
One popular trope is the 'rival - turned - friends' concept. At first, Bakugo's aggressive nature might make him seem like a rival to Kirishima, but as they get to know each other better, they become close friends. Another is the 'protective' trope. Kirishima might be shown as being protective of Bakugo, especially when Bakugo's temper gets him into trouble. And vice versa, Bakugo could be protective of Kirishima in dangerous situations.
In the manga, Bakugo and Kirishima don't get together romantically. They have a strong friendship based on mutual respect and shared experiences in battles and training.
You can write about their training together. For example, describe how they push each other to become stronger, and the friendly competition between them. This would show their growth as heroes - in - training.
No way. The manga portrays their connection through mutual respect and competition in their journey to become great heroes. A kiss is not part of that narrative at all.