1girl, armpits, arms_behind_head, arms_up, bikini, black_hair, breasts, cleavage, idolmaster, idolmaster_shiny_colors, light_rays, long_hair, looking_at_viewer, medium_breasts, multi-strapped_bikini, navel, outdoors, ponytail, red_bikini, shirase_sakuya, side-tie_bikini_bottom, smile, solo, sunlight, suwa763, swimsuit, very_long_hair