After the kiss, they could start to explore their surroundings together more often. Maybe they find a secret place that only they know about and spend time there, sharing stories about their past experiences.
No, they can't. Pokémon breeding has specific rules in the Pokémon universe. These rules are designed to keep the species somewhat distinct in terms of how they reproduce. Eevee is in the Field and Fairy Egg Groups, while Vulpix is in the Field Egg Group, but just being in the same Egg Group doesn't mean all Pokémon can breed. There are other factors and restrictions that prevent a male Eevee and a female Vulpix from mating.
The plot might involve the male Eevee being a bit of a wanderer and the female Vulpix being a protector of her den. Eevee stumbles upon Vulpix's territory. At first, Vulpix is defensive, but Eevee's friendly nature wins her over. The kiss is a culmination of their growing feelings. After that, they might team up to find a special artifact in the forest that is said to bring great fortune, all while dealing with other Pokémon who are also after the artifact.
If they could mate, we might expect a new Pokémon with a unique combination of traits. Maybe it would have Eevee's adaptable potential and Vulpix's fox - like features. However, this is all just speculation as it goes against the current Pokémon breeding rules.
One possible fanfiction could be about Eevee and Vulpix teaming up on an adventure. They might start in a forest where they encounter a group of Pidgey that are causing trouble for the other small Pokémon. Eevee, with its adaptable nature, could use different moves to try and scare the Pidgey away, while Vulpix uses its fire - based attacks to create a barrier. As they work together, they start to understand each other's strengths and weaknesses better, forging a strong friendship along the way.
One common theme is friendship. Since Vulpix and Eevee are both cute and popular Pokemon, many fanfictions focus on their bond. They often go on adventures together, relying on each other.
One popular theme is the journey they go on together. Maybe they're on a quest to find a special place or item, and their love grows during the adventure.
Maybe in the fanfiction, Eevee and Vulpix are both lost in a mysterious forest. They start to look for a way out together. Along the way, they come across ancient Pokémon ruins. Inside the ruins, there are puzzles and traps. Eevee, being a very adaptable Pokémon, uses its different forms' abilities (even if it doesn't actually change forms yet in the story) to solve some of the puzzles. Vulpix uses its fire to light the way and keep away any dangerous Pokémon that might lurk in the dark corners of the ruins. As they progress, they become closer friends and finally find their way out of the forest.
A really interesting fanfiction is the one where Vulpix and Eevee get lost in a strange part of the Pokemon world. They encounter new Pokemon species they've never seen before. As they try to find their way back home, they learn more about each other and their own capabilities. It's full of adventure and discovery.
There are some specialized Pokémon fanfiction communities as well. For example, some Discord servers dedicated to Pokémon fan creations. In these communities, fans often share their works, including fanfiction about eevee and vulpix in love. You can join these servers and start exploring. Additionally, Tumblr also has a lot of fan content, and you might come across some wonderful eevee and vulpix love fanfiction by using the right tags and searching thoroughly.