I know this thread is a little old but...

I have the same experiences with my wife man it's some hot stuff!

I also found out by accident and started going to bed and pretending to sleep but facing her on the edge of my pillow near her.

She would get going soon after confirming I was asleep with a nudge. When she would orgasm it was pretty obvious as the bed would jitter. Nice feeling.

I started to become a-tuned to her masterbation pattern (i.e. time of night). When she would start I added my own groans (as though I was having a sexual dream as in an in-direct result of her masterbating), made sure I had a juicy hard on. She would then slowly feel down there and confirm then leave herself and start jerking me off. I added a few dry humps to also suggest (you would be surprised what you can get away with while you 'sleep').

Later this developed into full-on sex, while I 'slept' but to make it real I made a point to 'wake up' on orgasm with surprise and 'unable' to hold it back. I would deny to her that I felt her during and that only at the end I woke up.

This turned her on like Chirstmas lights!!

I got more sex this way and the bonus was yes, I was awake and she didn't know :P

It moved on to blow jobs (which was rare for her), and she also used my hands on herself a few times when they were on her thighs.

So to play it all the way guys, just be in such a convenient position and don't be affraid to groan about your fake sexual dream which happens to be at the same time she is playing

Your wife will become less shy during this time, so much fun.

Tip:

They do this often when they have had very good sleep during the week. If they have been going to bed too late and not sleeping well then forget it! My wife is sick now the last week having trouble sleeping due to chest infection and she has not done anything lately.

enjoy