They might be characters from a specific genre of story. For instance, if it's a romantic comedy, Sonny could be a bubbly girl and Chad a bit of a shy but charming guy. They could be neighbors or coworkers, and their relationship develops in a humorous and heartwarming way.
Sonny might become more confident in her relationships. The kiss could make her realize that she can be bold in matters of the heart. Chad, on the other hand, might become more vulnerable. He has always been a bit of a ladies' man, but this kiss could change his approach to relationships.
Sonny might be a werewolf pup who has a problem with Mommy, who could be Leah as a mother - like figure in the werewolf pack. The 'shut up' comment could stem from Sonny's disagreement with Mommy's decisions regarding pack matters, like how to deal with the vampires in their territory.
One plot idea could be that after the kiss, they struggle to define their relationship in the context of their showbiz world. They might face pressure from the studio or fans.
I'm not entirely sure as there could be various interpretations. It might be about the adventures or experiences of a character named 'Sonny Boy'. Maybe it delves into his personal growth, relationships, or the challenges he faces in a particular setting.
Another theme is personal growth. In these fanfictions, both Will and Sonny often face challenges that help them grow as individuals, and their relationship evolves as they change. For example, Sonny might learn to be more spontaneous like Will, and Will might learn to be more responsible like Sonny. It's really fascinating to see how they influence each other in different storylines.
I'm not sure specifically which Sonny Chiba quotes are in 'Pulp Fiction' as there may not be a very direct and obvious connection. Sonny Chiba is known for his martial arts acting, and 'Pulp Fiction' is a crime - drama with a very different style. It could be that there are some quotes from his works that are alluded to in a very subtle way in the movie, but without further research, it's hard to say.