Her mother comes back the next day.

She knocked this time although she could see what I was doing through the open front door. I said come in and she opened the screen door, came in and sat in the chair closest to me, never taking her eyes off of my hand pumping up and down on my rock hard cock. She then asked that I not contact her daughter, as she is only 18, and needs to concentrate on graduating. I agreed with her on what her daughters priorities should be, that I had no way to contact her even if I wanted to seemed irrelevant. She thanked me for understanding, still staring at my cock as I stroked it. There was a long silence as she watched me masturbate, after about 10 min I asked if she was enjoying what she was seeing. Her face turned bright red and she stood up and said she had to leave, thanking me again, but not specifying what she was thanking me for as she walked out the door...