I had been helping a neighbor lady who was working on getting her Master's degree before heading back to India. Simple things such as giving advice and helping to proof the English in her papers.
So she graduates and wants to celebrate by going out to dinner. After dinner she mentions she wants to spend the night. As she put it, she was leaving soon and wanted to do something wild before she went back. She had never had sex with a white person before and she had chose me to break that barrier. Her reasoning was that I was old enough I would not expect it to develop into anything else.
So we get back to my place and my son and a good friend were there. They had been out drinking together and decided to drop by my place. Son had planned to spend the night with me which is not unusual just bad timing. So they decide to make a party with her there. (Extremely hot looking and wearing a low cut top). I try to get them to bail but they each figure they have a shot at picking her up. They told me later it never occurred to them she wanted me since I was so much older than her. (I was 59 to her 25). She finally gets frustrated and leaves. I walk her out to her car and she pulls a negligee out of her purse to show me what I was going to miss.

So a few months later I'm having dinner with that son and his older brother. I'm telling the story to my older son and lamenting the chance a old fart like me would ever have that chance again, only to be cock blocked by my son. So the older son and I hatched a plan that when my middle son turns 59 his older brother will take him out for a night on the town, (arranged with his wife's understanding if he is married at the time). My son will be approached by a hot young lady who is part of the joke. She will make it out that she is super interested in him and can't wait to leave with him for a wild night together. At that point where he is most invested in the scene she will hand him a birthday card from me and get up and leave. The card will have the following inside it. "Son, Happy Birthday and Fuck you very much. Love Dad."