My first wife always denied that she played with herself, so I got myself the smallest Camera I could find at the time, and managed to hide it in the bathroom.....I did indeed catch her on video doing almost exactly this, and the camera picked up her panting, grunting and ultimately her heavy moaning as she brought herself to orgasm....it was so sexy and wonderful to watch the footage....I then hid the camera in our bedroom, and caught her using the pillow to hump on, and on many occasions, using her hairbrush handle as she was laying on her back with her nightie around her waist.....I was quite surprised to also see her playing with her rather large breasts, lifting one to suck on her own nipple on quite a few occasions!
Note to the makers of these videos: The sound of a woman having a "genuine" orgasm is one of the sexiest things on this planet - NOT THE SOUND OF A FUCKING SHOWER!!
I often wondered what percent of women masturbate in the showers...one of my girlfriends confided to me that she did. She said it was the ONLY place she had privacy!