1girl, ball, barefoot, blonde_hair, blue_one-piece_swimsuit, blush, exercise_ball, feet, full_body, green_eyes, hairband, idolmaster, idolmaster_cinderella_girls, leaning_back, legs, one-piece_swimsuit, open_mouth, sakurai_momoka, school_swimsuit, short_hair, simple_background, sitting, smile, solo, swimsuit, tenjou_ryuka, thighs, toes, white_background