I'm not sure specifically as it depends on the individual who wrote it. Generally, a 'fanfic' is a fan - created story. 'Hajimete no Gal' is a series, and if it's a fanfic about Junichi from that, it might be about his relationships, adventures, or personal growth within the context of the 'Hajimete no Gal' universe.
Another theme is self - discovery. As the story progresses, the characters learn more about themselves and their feelings. For example, the main character may find out things about his own capacity for love and commitment that he didn't know before. It's a journey of growing up in terms of emotions.
In 'My First Girlfriend Is a Gal' story, we can expect to see the development of the relationship between the main character and his girlfriend. There could be challenges they face together, such as dealing with friends or family reactions. It may also show how they grow as individuals through their relationship, learning about love, trust, and communication. The story might be filled with sweet moments, like sharing secrets or small gifts, and also some not - so - smooth times, like misunderstandings, but ultimately it's about the journey of this first relationship.
There are several places you can look for it. First, check the official forums or communities dedicated to 'Hajimete no Gal'. Fans might share their fanfics there. Then, as I mentioned before, the major fanfic sites like AO3 and FanFiction.net are good bets. You can also try using search engines like Google, but be specific in your search terms. Type in 'hajimete no gal lemon junichi fanfic' along with keywords like 'read' or 'fanfic source'. Just be cautious when accessing fanfics from less - known sources as they may not be reliable or may violate some rules.
One similar novel could be 'My Youth Romantic Comedy Is Wrong, As I Expected'. It also has an English dub and features interesting character relationships and humorous dialogue.
You should stay calm. Reacting impulsively will only make things worse. If you love her, try to understand that it was her past. Don't let it overshadow your present relationship.
If it was more of an affectionate spank, she could have blushed and then given her partner a big smile or a hug in return. It might have made her feel closer to her partner, like it was a new and exciting way of showing their connection.