He was as serious as pie, but John was more than okay to keep this at a semi-friendship level rather than mess it all up by coming onto her. That didn't mean he didn't make comments to unnerve her with, but he had always hid them with a joking smirk so that she would never take him seriously.
John had more than enough options when it came to bed partners. Someone that could keep him talking like this was rare.
"Looking for any excuse to touch me, huh Kit? Sorry, but I don't do women old enough to be the headmasters' mother." He patted her condescendingly on her own cheek before he pulled away to finish making his snack.