19_okeke, 1girl, o, arisugawa_natsuha, bikini, blush, breasts, cleavage, collarbone, halterneck, idolmaster, idolmaster_shiny_colors, long_hair, looking_at_viewer, medium_breasts, o-ring, orange_hair, pool, pool_ladder, poolside, sitting, soaking_feet, solo, strapless, swimsuit, very_long_hair, water, white_bikini