2girls, d, ass, bikini, black_bikini, blush, breasts, closed_mouth, eyes_visible_through_hair, hair_between_eyes, hair_bun, hug, idolmaster, idolmaster_shiny_colors, looking_at_viewer, medium_breasts, multiple_girls, night, night_sky, open_mouth, osaki_amana, osaki_tenka, outdoors, palm_tree, partially_submerged, red_hair, siblings, side-tie_bikini_bottom, single_hair_bun, sisters, sky, smile, star_(sky), starry_sky, swimsuit, tree, twins, wanimaru, wet, white_bikini, yellow_eyes