The relationship between Ash and Serena is a big part. Fans love seeing Ash in the role of a hero saving Serena. It adds a new dynamic to their relationship.
You can try looking on fanfiction websites like FanFiction.net or Archive of Our Own. Just search for 'Ash Saves Serena' in their search bars and you might find some great stories.
In this fanfiction, Ash could first assess the situation carefully. He might notice that Team Rocket has set up some sort of elaborate scheme to capture Serena. So, he starts by sending out his Pokémon like Bulbasaur to use Vine Whip to disarm any mechanical devices Team Rocket has. Then, he could bravely run towards Serena while his Pokémon keep Team Rocket at bay. He might also encourage Serena to be brave and follow his lead as they make their escape. Once they are out of immediate danger, he could make sure Serena is okay and comfort her after the scary encounter with Team Rocket.
They would probably be a bit shy at first. Ash being his usual energetic self but also respectful of Serena's space in the tent. Serena might be a bit nervous but also excited to be sharing such a close space with Ash.
In fanfiction, anything can happen. However, without specific details of the particular fanfic, it's hard to say for sure if Serena is pregnant. Some fanfictions might explore this plotline for the sake of drama or character development. It could add an interesting twist to the relationship between Ash, Serena and Lemon, but it also depends on the overall theme and direction the author wants to take the story.
One great Ash and Serena fanfic is 'A Journey Together'. It beautifully captures their relationship growth as they travel through the Pokémon world. The author does an amazing job of showing Serena's determination to support Ash in his Pokémon battles and how Ash starts to see Serena in a different light.
For Ash, he could develop better communication skills. In the Kalos League, he often gets so focused on battles that he forgets to share his thoughts and feelings with Serena. By learning to communicate better, he can strengthen their relationship. For Serena, she could develop more self - confidence in her own Pokémon training skills. Maybe she starts out doubting herself but as the Kalos League progresses, she becomes more assertive and makes her own mark in the Pokémon training world.
Serena could be a bit shy at first. She might blush deeply and look down for a moment. But then, she would look into Ash's eyes with love and admiration. She would tell Ash how much she loves him and how she has been hoping for this moment. She would accept his proposal gracefully, and they would share a tender embrace while their Pokémon friends cheer around them.
A great idea could be a fanfiction about Ash and Serena traveling together to a new region to discover rare Pokémon. They could face challenges, make new friends, and help each other grow as trainers. This would focus on their relationship in the context of the Pokémon world and their shared goals.