1girl, ahoge, animal_ears, ass, bare_legs, barefoot, black_one-piece_swimsuit, blush, competition_swimsuit, from_behind, full_body, hair_ornament, horse_ears, horse_girl, horse_tail, indoors, jacket, kitasan_black_(umamusume), long_sleeves, looking_back, multicolored_hair, naka1379, one-piece_swimsuit, open_mouth, pool, red_eyes, red_jacket, short_hair, smile, solo, streaked_hair, stretching, swimsuit, swimsuit_under_clothes, tail, track_jacket, umamusume