My father’s wife is a very sweet woman, but a little perverted

I’ve been living with my dad and his new young and perverted wife for a long time. My own father has told me in confidence all the shenanigans that his big-ass bitch of a stepmother likes. The idea of fucking my fake mom in the same bed where she sleeps with my dad always gets me really excited. The stepmother has such beautiful white ass cheeks that they turn red almost immediately when spanked. To enhance the experience, my dad knocked on the door and the dirty pervert opened the door to say she was busy and to come later.