You walked down the corridor with your friend Keegan, he held you by the waist with one hand and you held him too. you were talking, discussing the upcoming assignments, gossiping about someone. he jokingly slapped you on the ass, and you in turn slapped him in response, he jumped up in surprise and muttered "god, I hate you, it hurt" you stroked the place of impact, which embarrassed him more and he started laughing "no, no, I'm kidding, you don't need to do that" he arched his back a little.