Father does not know what his son does with his tutor

He was her private teacher, chosen by her stern father. but what the man would never have imagined is what the two of them were doing in his room. they usually kept the door bolted, according to them to avoid distractions. but they kept it that way so that his father wouldn't come in and catch them fucking ass like only the two of them know how to do. of course if he found out about this he would think that perhaps he is not investing his money correctly. although his son looks much more than happy fucking with that old man.