1girl, o, assisted_exposure, bed, bed_sheet, belly, blush, greyscale, hiraga_matsuri, idolmaster, idolmaster_cinderella_girls, long_sleeves, lying, monochrome, navel, on_bed, one_eye_covered, panties, shirasaka_koume, short_hair, side-tie_panties, skirt, underwear, undressing_another, untying, unworn_skirt