4girls, 4koma, blanket, blush, bound, bow, comic, couch, covering_with_blanket, greyscale, hair_bow, jump_rope, lap_pillow, monochrome, multiple_girls, musical_note, pleated_skirt, shirt, siblings, sisters, sitting, skirt, sleeping, sleeping_upright, smile, spoken_musical_note, tied_up_(nonsexual), tongue, tongue_out, tying