Manga Saitama's progress speed is hard to define precisely. It can be rapid in intense moments but might slow down to flesh out details and relationships in different parts of the story.
I'm not sure specifically about 'Naruto and Fubuki' lemon fanfiction. However, it's important to note that lemon fanfiction often contains inappropriate or adult - themed content. You might be better off looking for more general, non - explicit fanfiction that focuses on the relationship or adventures of Naruto and Fubuki in a more positive and family - friendly way.
One Punch Man is a really popular anime. Fubuki, as a character in it, has a lot of potential for fanfics. In a fanfic about them, it could explore their relationship in new ways. Maybe it could show Fubuki trying to recruit Saitama into her group in a more detailed and different way than in the original story. It could also develop her character further by showing her reactions to Saitama's overpowering strength in unique scenarios.
A Saitama and Tatsumaki married fanfiction could have multiple plotlines. One could be that Tatsumaki, who is used to being in control, finds herself falling for Saitama's carefree and powerful self. Their courtship could be full of misunderstandings at first. Saitama, being oblivious as he often is, might not immediately pick up on Tatsumaki's feelings. Once they get married, they would face challenges like how to balance their hero duties with their new family life. Tatsumaki might want to keep their relationship a secret from some of the other heroes at first, while Saitama might be more open about it. There could also be a sub - plot about how they handle Tatsumaki's overprotective sister if she finds out about the marriage.