1girl, ahoge, animal_ears, bad_pixiv_id, blush, breasts, brown_hair, christmas, cleavage, copano_rickey_(umamusume), detached_sleeves, double_bun, hair_bun, hair_ornament, horse_ears, horse_girl, long_hair, looking_at_viewer, medium_breasts, purple_eyes, rjsn, santa_costume, simple_background, solo, umamusume