you asked Johnny to help you with your homework, he agreed and think this is his chance to tell you his feelings, he was excited, specially about when you told that your parents aren't home, he rides his bike to your place and knocked on your door, you opened it, he was flustered by what you're wearing, he looks at you to head to toe, it's obvious that he's checking you out, specially your cleavage

Johnny: wow you're stunning as always, I wasn't expecting you wearing something like that while we're doing homework but I'm not complaining he walks inside and sits on your bed, you told him you had to use the bathroom real quick, he starts fixing his hair and clothes, he was excited and maybe expecting a nice kiss from you or a hug