In a 'fem kyuubi loves naruto kushina bashing fanfiction', the plot might revolve around the fem Kyuubi's possessive love for Naruto. She may feel that Kushina's memory or influence over Naruto is too strong. So, she could start by subtly making Naruto question Kushina's love for him. For instance, she might say things like 'Your mother left you alone in this world' even though Kushina had no choice. Then, as the story unfolds, she could try to replace Kushina's place in Naruto's heart by being overly affectionate and helpful to Naruto. But this would likely create internal conflict within Naruto as he tries to reconcile his love for his mother and his new - found relationship with the fem Kyuubi.
Well, it could start with the fem Kyuubi being in love with Naruto. Since she has negative feelings towards Kushina, she could begin by influencing Naruto's view of his mother. For example, she might show Naruto 'alternate' versions of Kushina's past actions that are not entirely true. As the story progresses, the fem Kyuubi could try to isolate Naruto from anything related to Kushina, like the Uzumaki clan heritage that Kushina represents. And perhaps, in the end, she realizes the error of her ways when Naruto discovers the truth about his mother. However, this is just one possible set of plotlines in such a complex and potentially controversial fanfiction concept.