At first, it might be a relationship based on mutual need. Vegeta needs Bulma's resources and intelligence to get back on his feet, and Bulma is intrigued by this alien. As time passes, they start to understand each other better. For example, Vegeta may start to open up about his past and his Saiyan pride, and Bulma will share her dreams and ambitions with him.
Often, in fanfiction, a common plot is that Naruto uses the Final Flash to save his friends in a dire situation. Maybe his friends are trapped by a powerful enemy's jutsu, and the only way to break through is with this powerful attack. It could also be a plot where Naruto teaches the Final Flash to one of his students, like Boruto, and how that changes the new generation's fighting capabilities.
I don't think there's a sequel. Comics often depend on various factors like popularity and the creator's plans to determine if a sequel will be made, and it seems that for Flash First Steps, a sequel hasn't been announced or produced yet.
The First Marriage, the First Love, the First Military Marriage, and the Flash Marriage was a novel by Mo Ying. The story was about the female protagonist, Yan Zhen, who was determined to get back at those who had bullied her after her rebirth. She married Gu Weichen in a flash, hoping to live a happy life. In addition to this novel, there were other similar military marriage novels recommended, such as " Second Military Marriage: Torturing the Ex-Husband and Marrying the Fierce Soldier Brother "," 70 Military Marriage Is Sweet as Honey, Bringing a Baby and Doing Scientific Research Without Mistakes ", etc. These novels were all about military marriages and flash marriages, which contained elements of love, sweetness, and sadomasochism. If you want to know more about the first marriage, you can read the full text or comic on the relevant website.