1girl aqua_neckerchief arms_up ascot blue_skirt blush brown_hair commentary_request grey_background hashi hibike!_euphonium kitauji_high_school_uniform looking_at_viewer midriff midriff_peek nakagawa_natsuki navel neckerchief photoshop_(medium) pleated_skirt ponytail purple_eyes school_uniform serafuku short_sleeves simple_background skirt solo stretching