It's nice to know this phenomenon has a formal name.
A few years ago, I responded to a Craigslist ad from a man who was looking for another bi male to be in a three-some with him and his wife. After exchanging e-mails to get acquainted, I was invited to meet him at their house in a nearby town. This was to be sort of an audition; his wife would not be there. We went upstairs to their huge master bedroom, where we stripped down to our shorts, laid on the bed, felt each other up and talked. After awhile, he went to the nightstand and took out a packet of photos (prints) of his wife and offered them to me to look at. She was attractive, a bit plump but curvaceous, and posed provocatively in bra, panties, garter belt, and naked for the pictures, which had obviously be taken in this very bedroom. I started to get hard in my shorts, he likewise in his, watching my excitement, and soon we had the photos spread out on the bed and were masturbating naked, individually and then each other. He was smaller in stature than me, and my cock was quite a bit bigger than his. His curved up to his belly button, mine pointed straight out. I was thinking this is going to be a long and interesting afternoon, expecting his wife to be home from work any moment and the real fun would begin. Instead, he came very quickly once we got to doing it nude, a couple of minutes at the most. He lost further interest almost immediately. I washed up at the bathroom basin while he showered quickly. The we got dressed and I went home.
Several weeks passed without a word, then he called saying he was in my neighborhood showing a property and would I like to get together on his lunch break. I had the house to myself for a few days and said sure. He wanted to get naked and masturbate together again, and brought the pix of his wife including some I didn't see the first time. Things happened quickly just like before and then he was on his way back to work. Never heard from him again after that.
I have to say that the photos were more stimulating to me than any porn I ever saw. It turned me on to be looking at a "real" woman other than my wife in such intimate "real" circumstances.