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.
A memorable interaction could be when a senior straight person attended a gay pride event with their gay friend. They held hands and walked together, showing support publicly.
He could meet his descendants like Goku or Vegeta. It would be an interesting encounter as they have different upbringings and personalities compared to Bardock.
Often, Goku is paired with Bardock. Since they are father - son, it makes for an interesting dynamic in the fanfic. Bardock can see how his son has grown and influenced the universe, and Goku can learn about his Saiyan heritage directly from his father. Another character could be Vegeta. They can bond over their Saiyan pride and work together to protect the Saiyan race or take on common enemies.
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.