Yesterday my 60 year old mother walked in as I was masturbating.I was home alone as my wife had gone shopping and had decided to have a leisurely wank,I was on the sofa stark naked watching a porn movie my stiff cock in my hand,when I suddenly realized my mother who has a spare key had come in and was framed in the doorway staring at my erection,I made an attempt to grab my clothes from the floor,she just said "oh sorry dear,I should have knocked".I quickly dressed and tried to say sorry but she said "don't worry all men do it"Then to my my amazement she told me that she had seen me wanking as a teenager on a number of occasions,she promised it was our little secret and she wouldn't tell my wife.