Well, Kyuubi might be possessive of Naruto because they have a unique bond. Kyuubi has been inside Naruto for a long time. They've shared experiences, and Kyuubi may see Naruto as its own in a way. Also, Naruto has sort of tamed Kyuubi to an extent, and this might make Kyuubi feel like Naruto is special to it, so it shows possessiveness.
One possible reason could be that in the Naruto universe, Naruto has a special connection with the Kyuubi. As a female Kyuubi in fanfiction, she might feel a stronger emotional bond towards Naruto. She may see Naruto as her sole companion or the one who truly understands her, which leads to her possessiveness.
In this type of fanfiction, the fem Kyuubi's possessiveness might be manifested in her protecting Naruto at all costs. She could be overly vigilant and not allow any harm to come near him. This could lead to her interfering in battles or situations where Naruto might be in danger, even if he doesn't necessarily need her help all the time. She may also try to monopolize his time, not wanting him to go on missions with other people or make new friends. Her possessiveness could also be expressed in a more emotional way, like getting sulky or angry when Naruto doesn't pay enough attention to her.
In many fanfictions, the Kyuubi's possessiveness is a result of their unique bond. Since they share a body, the Kyuubi might see Naruto as an extension of itself. So, it could be shown as the Kyuubi being extremely territorial about Naruto. It might not tolerate any external entity trying to control or manipulate Naruto, and will assert its power to keep Naruto under its 'protection' in a very possessive manner.
One example could be a story where the male Kyuubi constantly hovers around Naruto, not allowing others to get too close to him. He might interfere in Naruto's relationships, seeing Naruto as his and his alone.
One common plotline could be the conflict that arises between fem Kyuubi's possessiveness and Naruto's own desires for freedom and friendship. Naruto might want to explore and interact with others, but the fem Kyuubi tries to hold him back.
He might also try to reason with her. Naruto has a big heart and he would likely want to understand her feelings. He could say things like 'We're friends, we don't need to be this way.' He'd try to get her to see that her possessiveness is not healthy for either of them.
No. In the Naruto series, Naruto is the host of the Kyuubi, not its slave. Fanfics might deviate from the original concept, but in the official story, Naruto has a symbiotic relationship with the Kyuubi. He gains power from it and eventually befriends the Kyuubi spirit.
One great Fem Naruto Kyuubi fanfic is 'The Nine - Tailed Fox's New Host'. It explores how a female Naruto deals with the power of the Kyuubi in a unique way. The story focuses on her training and how she overcomes various challenges with the help of the Kyuubi's power.
One possible aspect could be a story about Naruto befriending the female Kyuubi. In many fanfics, they might start with Naruto trying to understand the Kyuubi's female form better. Maybe he discovers that she has a different personality compared to what he expected from the regular Kyuubi. For example, she could be more gentle and protective in a way that surprises Naruto.