I've always been a fan of gyarus in my hentai. Their style, their often playful attitude, it often gets me excited. I don't have any particular plots in mind, but I can list a few brief ideas that we can maybe work off of, or maybe you have your own idea you'd like to suggest.
- Gyaru asking nerdy guy to tutor her, in exchange she'll help him indulge in his nerdy desires.
- Two childhood friends become sperated when one moves away. Years later, they're finally reunited, with the girl now being a gyaru.
- Gyaru, along with her friends, have been picking on a nerdy guy in class. When she sees a porn magazine in his bag and sees that he's into the same kinks she's interested in, she starts to become about him.
- Gyaru, having run away from home, and is living on the streets. Being picked up by a guy and offered a place to stay, she's more than grateful for his generosity, and is more than happy to repay his kindness with her body, letting him use her as much as he wants as long as she can stay with him.
- Slutty gyaru picks up a random guy for some fun. To her surprise, he ends up being one of the best lovers she's ever had. Now she finds herself wanting to meet with him more and more.
Let me know if any of these ideas interest you. I'll also post a few pictures of gyarus as examples of the types of girls I'm looking for. Feel free to use any of them as reference for your character, or bring one of your own if there's one in particular you like. Hope to hear from you soon.