Well, one idea could be that Ash and May participate in a special school event. It's a competition that combines Pokemon battles and contests. They have to work together against other teams. Along the way, they face challenges that test their friendship and skills. Ash might learn some new contest moves from May, and May could pick up some battle strategies from Ash. It would be a great story of growth and cooperation for both of them.
Their high school story could involve new friendships. Ash, being his friendly self, would make friends with all kinds of students, including those who are new to Pokemon. May could use her charm and knowledge to help these newbies. And of course, there would be some kind of big mystery or threat in the school, like a group trying to steal rare Pokemon from the students, and Ash and May would have to team up to stop them.
Their relationship could become more competitive in high school. With both of them having their own goals in the Pokemon world. They'd constantly try to outdo each other in various school - related Pokemon activities. But this competition would also make them respect each other more in the long run. Ash might learn new strategies from May's contest - based approach, and May could pick up some battle - hardiness from Ash.
One common theme is friendship. Ash and May's friendship growing in high school, through sharing pokemon experiences. Another is competition, as they might compete in school - based pokemon battles.
One possible scenario could be that Ash and May are in high school and they join the school's Pokemon battle club. Ash might be eager to show off his battle skills, while May could be more interested in learning new strategies and studying different Pokemon types for her contests. They could have friendly competitions within the club and also team up against other schools in Pokemon battles.
Ash and May's relationship might develop as they help each other out with their respective goals. May could help Ash understand the more artistic side of Pokemon, like in contests. In return, Ash could teach May about battle strategies. As they exchange knowledge and experiences, they would become closer friends. They may start to rely on each other more and more, and this mutual reliance would be the foundation of a strong relationship.
They could participate in a high school Pokemon tournament. Ash would be super competitive, using his Pikachu to its full potential. May might enter with one of her cute Pokemon like Skitty. They could face off against each other in an intense battle, which would be a really exciting part of the fanfic.
One popular 'pokemon ash x may high school fanfiction' is 'Ash and May's High School Adventure'. It shows their journey in high school, dealing with classes and pokemon battles together. Another one could be 'High School Days of Ash and May' which focuses on their relationship development during high school.
In the high school, there could be a Pokémon daycare center where students can leave their Pokémon during classes. Ash and Dawn could volunteer at this daycare, taking care of the Pokémon and teaching them new tricks. This would also be a place where Pokémon interact with each other, leading to some fun and chaotic situations.
Ash could be a transfer student in the Pokemon school. He'd be excited to learn new things. He might join a special class focused on rare Pokemon. His Pikachu would be his constant companion, and they'd get into all sorts of fun and mischief in the school hallways.