New years eve fun

Hi all this is a true story, happened this new year.

My wife and I went down to stay with some friends for the new year, we tend to alternate things each year, with different friends we know. This year we ended up in Kent, staying over for a few days with some friends of our O and A (yes, it's true - lol).
The evening went well and our friends, along with my wife S, and me, enjoyed the company of some new and old friends for the night, getting rather drunk in the process.
Around 2am, A (my friend's wife) decided she had, had enough and said she was going to bed. As she had put in a lot of effort for the party, O and I decided to tidy up and S, my wife went to change and make sure the kids were ok.
When she came back down, she was wearing a nightie and this was covered to her knees by a toweling robe. We all decided that as we had finished the tidying, we would have a nightcap. I sat on the sofa, with S putting her legs over mine and O sorted the drinks. We sat chatting for about 1/2 hour, but S then fell asleep. She always looks so peaceful when she's sleeping. She is 35, blonde, slim 8/10, 34dd and great legs, which were currently showing quite a bit. I shifted in my seat and the result was S turned towards me, revealing her legs, right up to her thighs. As I said, she has great legs and O, I noticed, was shifting uncomfortably in his seat, which was effectively to my right. He could probably see right up to the top of her thighs. I decided to keep the mood going and rested my hand on her leg, slowly rubbing it, gently, whilst continuing to chat to O.
After a few minutes, I got a little more daring and slowly moved the nightie upwards, revealing more leg and I guess, a glimpse of her pert, round arse. O was now making any excuse to get up (picking up a pice of litter we'd missed, refilling our glasses) and the second time, sat down immediately at my right. Nearer than he had been before and craning forwards as we talked. Suddenly S shifted again and moved onto her back. He dressing gown opened but the nightie had lowered back down.Both of her legs were now over mine, her backside resting on my hip, elevating her slightly. I placed my hand on her inner thigh and gently caressed her leg. O could not take his eyes off her. I thought I would be more daring and started moving my hand up her nightie, having the effect of exposing more of her inner thigh, until gradually, her pubic hair could be seen. O was now red faced and not looking at me all. I moved her nightie back more, exposing her beatiful mound completely, my heart beating so loudly that I thought it would probably wake her. I looked down at her face and to my astonishment, she opened her eyes, winked at me and then closed them again. She had been awake all the time!
Slowly, I edged her legs apart at the knees. Her stunning pussy was now fully displayed. Her moist lips were open and I was hard as a rock.
Casually, I rubbed her lips gently with my fingers, edging her lips apart further, before inserting two fingers in and started to gently masturbate her. She kept still for a couple of minutes as I got deeper and deeper, until she suddenly brought her knees up together and "woke up". My fingers were soaked.
She then got up, saying that she was tired. Said goodnight and went to bed. I got a glass of water and followed her up, leaving a stunned O sitting on the sofa, open-mouthed. The next morning nothing was mentioned by anyone and she has said nothing about it at all since.