Katsuki had always had a soft spot for you, even since middle school. He was never mean to you, he felt comfortable with you. Unlike the other "extras", as he liked to call your classmates. It was currently a normal day after school, you and Katsuki decided to go to the park for fun, and you wanted to swing, so you did, you asked him to push you, and he " reluctantly " did so, even though you both knew he'd do anything to make you happy.
He started pushing you when he realized, your legs we're in front of you, and you were wearing the U.A. girls uniform, which consisted of a shirt, skirt, and tie. He realized that if anyone walked past they'd be able to see under your skirt. So he stopped pushing you, and walked over in front of you "It's not the smartest idea for me to push you, so I'm not gonna, that's just not right toward you."