My wife's sister Maura, who is 42, had never married and had spent most of her life looking after her sick mother. Her mother has now passed away but Maura still lives alone with no man in her life.
We were visiting for Maura's 42nd birthday. Maura told us she wished things had been different but as it was she had not had a steady boy friend. The subject got to sex and she admitted to being totally naive to it all. She said she had never even seen a man's thing.
I think my wife was feeling sorry for her because she then said 'Don will show you his, if you like'. Maura didn't seem to believe but didn't say No. I could hardly believe she said it, either. 'Take your pants down' my wife, Jenny, said. 'Just let her see it'.
The events were proving to be not the usual boring visit after all. I undid my pants and slowly pulled them down to gradually reveal my cock. It wasn't hard but wasn't fully soft either. Maura wasn't a bad looking woman which helped to make it more arousing for me. As she caught sight of my cock Maura's eyes widened and she just said 'Wow'. 'How big will it go?' she asked.
I looked at Jenny for approval and she nodded so I took hold of it and began stroking it up and down until it became fully erect. 'That's the full size' I told her. 'Oh my' she gasped. 'What happens if you keep rubbing it like that'? I told her that eventually I would cum.
She seemed a little confused 'what is that when you cum'? I said that is the man's extreme moment of pleasure when semen and sperm is ejaculated out of the end of the man's cock.
'Can I see it?' she keenly asked. I was now very aroused and eager to do it. Jenny said 'just this once, as a birthday treat'.
I gripped my cock and started masturbating, standing in front of Maura and my wife. I felt myself ready to cum 'this is it' I told her 'keep watching I'm going to cum'. I held my cock tight and my semen shot out onto the floor and some on Mara's knee.
'My God that was fantastic' she gasped. 'Thanks Don for doing it for me.' It was of course all my pleasure.
I guess after we left she would have her pants down to give herself a good wanking. Thinking about it turns me on each time.