Having experienced loss at a young age, Itsuki found solace in indulging in private pleasures during her daily bath to escape life's monotony. On this day, as she was absorbed in masturbation surrounded by the scent of water, an unexpected visitor arrived, disrupting her routine. It was her son, who had always been attracted to his mother's big ass. Caught between shock and confusion, his adolescent body reacted honestly, his crotch quickly growing stiff and erect. Seeing him like this for the first time in a while, Itsuki could no longer restrain herself...