saitou natsuki, mikogami karin, imouto kansatsu nikki, triangle (company), game cg, 1girl, barefoot, blush, bottomless, brown hair, censored, chair, closed eyes, crotch rub, dutch angle, feet, female focus, female masturbation, flat chest, from below, hair ribbon, leg up, long hair, looking down, masturbation, mosaic censoring, no panties, on chair, open mouth, ponytail, pussy, ribbon, shirt, sitting, solo, spread legs, table, table humping, under table, window