When I was a kid, I had sexual infatuation with my mother. I used to find ways to "accidentally" walk in on her when she was getting dressed/undressed. When she got wise to that and started keeping her bedroom door closed, I came up with a scheme to window peep on her. When she went to take her evening bath/shower, I would slip into her room and carefully fix the curtains on the windows so that they appeared to be closed, but afforded me a view from the outside. I would then go to my room and slip out the window and go around to her bedroom. There were windows at three corners of her bedroom, so I could get a view from several different angles, whatever provided the best view. I would masturbate myself to the edge and wait for her to come out of the bathroom. As she got her nightie out of the bottom dresser drawer, I would bring myself to ejaculation while fantasizing that I was mounting her from behind and cumming deep inside her.
I window peeped on her for three or four years and masturbated myself to many ejaculations while spying on her.