1girl, ahoge, alternate_costume, animal_ears, black_hair, blush, breasts, character_doll, christmas, cleavage, hair_ornament, horse_ears, horse_girl, kitasan_black_(umamusume), kouzuki_hajime, looking_at_viewer, medium_breasts, red_eyes, santa_costume, satono_diamond_(umamusume), snow, thighhighs, umamusume, wall