It might start with curiosity. Hiccup is intrigued by this new human - like Toothless. As they interact more, they could develop a bond based on mutual respect. For example, they might find they both have a love for flying, even if Toothless is now human and has to find new ways to experience it.
It could develop gradually. At first, they might be cautious around each other. For example, Human Toothless may be a bit shy because he's not used to interacting with humans in this form. The female Hiccup might be intrigued by his connection to dragons. As they spend more time together, like when they are training young dragons, they start to trust each other more. And trust can easily lead to deeper feelings.
One common theme is adventure. Since they are based on the How to Train Your Dragon world, they often go on quests together.
One common theme is friendship. Since Hiccup and Toothless have a strong bond in the original, this is often explored in a different way when Hiccup is female and Toothless is human. Another theme could be adventure. They might go on quests together, just like in the original but with a different dynamic.
One key theme could be the exploration of an unusual relationship. Since Hiccup is usually associated with Toothless in the dragon form, having a human Toothless creates a unique dynamic. It might explore themes of acceptance as they navigate their differences. Another theme could be adventure, as Hiccup is known for her adventurous spirit and with a new kind of Toothless, new adventures might unfold.
Toothless would likely develop his communication skills further to better understand Hiccup's needs during the pregnancy. He might start to make more complex gestures or sounds. Hiccup would experience a great deal of personal growth. She would have to face the judgment of the village and learn to stand up for herself and her unborn child. The other dragons in the story could also develop in their relationships with Toothless and Hiccup. For example, they might initially be confused but then show support in their own dragon - like ways.
You can try looking on fanfiction websites like Archive of Our Own or FanFiction.net. Just search for 'fem Hiccup x human Toothless' in their search bars.
At first, it could start with mutual curiosity. Hiccup, being used to his Toothless, is intrigued by the differences in Female Toothless. She might be more skittish or have different behaviors. As they spend time together, they start to trust each other. For example, Female Toothless might let Hiccup ride her for the first time during a chase when their normal escape routes are blocked.
One characteristic is the exploration of a unique bond. Since Toothless is a dragon, a female version adds a different dynamic to the relationship with Hiccup. It often involves adventure as they fly together and face challenges in their world. Another aspect is the emotional connection. Writers usually focus on how they understand each other on a deeper level.
Fanfiction.net could also be a good place. However, the quality can vary greatly. Some stories might be really well - written with interesting takes on the Fem Hiccup and Human Toothless concept, while others might not be as good. It's all about sifting through to find the gems.
I'm not really into this specific concept, but in general, fanfiction often explores unique relationships. In this case, it might involve a very different take on the characters' bond, perhaps with Toothless in a more human - like form. However, it's a very niche and often not a canon - compliant idea.