We were on vacation and came across a river while hiking in the woods, No one else was around, so I decided to go skinny dipping. After getting in the water I noticed my wife was taking pictures of me, which she was planning to post on Facebook, but the water was moving sufficiently that the pictures didn't show anything.
As I was getting out of the water I dared her to take one more of me standing at the river's edge completely naked. She was real hesitant, but eventually I goaded her into taking it. Afterwards, she said that, of course, she would not post that picture. But the whole episode had been such a turn-on that I told her to go ahead; I didn't mind.
Nothing more was said, but for the entire trip, it was weird, but the thought of her posting the picture caused me to get turned on continually. So much so that after getting home, I again reminded her to be sure she posted the naked picture, and to feel free to share it with anyone she wanted.