My wife comes from a strict upbringing but over the years has opened up to me. We now role play and she has her fantasies. Her favorite is that she is humiliated in front of a group of men and then gangbanged. I help her experience the fantasy with masturbation.
I start by stripping her naked, except for her high heels, and leading her into our dining room. There on the table I have laid out an assortment of pleasure aids each to represent a different man. I generally have a banana, cucumber, carrot, candle and a vibrator. She sees these and knows what's coming. I make her lay down on the table and starting inserting each one in her. Ultimately I make her masturbate with one of these which is my choice after which I fuck her.
I have photographed and videotaped her while she's pleasuring herself. The videos I keep while I have mailed out pictures, blocking out her face, to strangers by calling 800 numbers at random. If whoever answers wants one I then mail it to him. Many people have her picture now and she delights in knowing this since she safe that no one will know it's her. I also know that she masturbates when I'm not at home now.
More importantly she looks forward to our sessions more each time.