3girls, ass, ball, bare_arms, bare_legs, bare_shoulders, barefoot, beach, beachball, bikini, black_hair, blonde_hair, blue_eyes, blue_sky, brown_hair, closed_eyes, dark_skin, day, gradient_hair, grey_hair, gyaru, idolmaster, idolmaster_shiny_colors, innertube, izumi_mei, long_hair, looking_at_viewer, looking_back, mayuzumi_fuyuko, multicolored_hair, multiple_girls, ocean, otsudou, outdoors, red_bikini, red_eyes, serizawa_asahi, short_hair, sky, straylight_(idolmaster), swimsuit, two_side_up, wading, water, wet, white_bikini