My wife has always enjoyed masturbation, but she used to be somewhat shy about it. She would sometimes go to bed early to 'read', but it was pretty obvious she was helping herself fall asleep by masturbating with the vibrator she kept in her nighstand drawer. There were times when I would listen quietly outside the bedroom door, and I could clearly hear her moaning and making a noise as she masturbated to a nice juicy orgasm.
She knew that I enjoyed masturbating in the shower, and I especially enjoyed doing it at night before bed, so I would often walk in on her as she was 'reading'. Sometimes I would go upstairs to take a shower and she'd be in bed, totally nude but innocently reading a novel. However, I'm pretty sure she had been reading something a little more erotic earlier, and she had probably even started masturbating a little. I think there were quite a number of times she probably masturbated while I was in the shower, knowing that I was going to be in there for a while.
Now that she knows how much it turns me on, she is much more open about her masturbation habits, and she is often pretty blatant about it as well as letting me know about her masturbation sessions that happen while I'm not home. She will leave her toys and magazines out on the bed, knowing that I will see them when I get home and know that she had enjoyed a masturbation session with herself just a little while earlier.
She also still enjoys masturbating while I'm in the shower, but now she makes it plainly obvious what she plans to do to herself in bed while I'm in the bathroom with the door closed.
Sometimes when I come upstairs to take a shower, I find her reading one of her erotic books and her legs are spread apart under the covers, so I know she has been touching herself already. If her nightstand drawer is open, I know she has the vibrator under the sheets with her, and that she will be masturbating with it soon. I like to walk around naked in the bedroom getting ready for my shower and she notices how horny I am and suggests that I might need to take care of myself in the shower. She tells me how she is going to need to masturbate while I'm in the shower and that I should feel free to masturbate and make as much noise as I want. As you can imagine, I've spurted a lot of big loads of cum in the shower, thinking about what she was doing to herself in bed.
I love reading stories from women who aren't shy about letting their husband or boyfriend know they enjoy masturbating when they are alone, and who will even do it if he is nearby.