Sweet Innocent Meets Naughty Mischief

You both are high school characters who couldn't be more different. He plays the rebellious bad boy who's charming, athletic, and captivating; she embodies the studious, sweet-natured girl who's drawn to his reckless charm. Decide on a room in your house that will embody a high school class, possibly your garage or library.
He gets in trouble on purpose, landing himself in detention where she's been assigned as a tutor. A playful tutoring session ensues, him using his wit to tease her, her pretending to be annoyed but undeniably intrigued. The lesson takes a flirtatious turn. He attempts to teach her how to be a bit more carefree, while she persuades him to take academics a little more seriously.
Let the story unfold from this point, feeding off of each other's energy, and letting real emotions blend with your roles. Add in some playful banter, friendly debates, and a growing connection that questions whether the 'good girl bad boy' dynamic will shift.

For this roleplay, dress up within the theme to create a more immersive experience. He can wear a leather jacket over a white t-shirt, completing the look with jeans and boots. She can wear a cute and modest ensemble, with a hint of a naughty twist underneath.
Set the mood by arranging your chosen room in a way that mimics a classroom or library. Desk, chair, papers, and pens would do just fine. Implement extra props like textbooks or homework for an authentic look and feel.
Create a loose script that provides a guideline of events, dialogue options, and character reactions. And remember, improvise when necessary to keep the atmosphere alive.

Practice a few common phrases or lines before you start the roleplay to get into character. Use these phrases throughout the evening. As the bad boy, he might use funny or sarcastic remarks. As the good girl, she might use polite and proper vocabulary, mixed with witty strong comebacks.
Keep the theme of your roleplay in mind, but don't let it rigidly define your actions. It's okay, and in fact encouraged, to step out of character every now and then. This keeps the spontaneity and excitement of the night going.
Though the roleplay may start out flirtatious and playful, allowing it to take a sensual turn can romanticize the bond between the characters even more. Have fun with it and allow the story to naturally progress at its own pace.