At first, my mother was completely passive, but her mood gradually changed through her expressions and attitude midway. There were many moments where I thought, "Huh? Isn't she getting more into it than I expected?" and that gap was really good. Rather than showing flashy developments, it's the type where you enjoy the process of her gradually getting turned on. The entire sequence of a chaste and serious mother falling into erotic depravity is superb, and the highlight is that transformation.