Literature Reference: 朱口发艳歌，玉指弄娇弦。—— 《相和歌辞 子夜警歌二首 二》 With her vermilion lips she sang a melodious song, and with her jade-like fingers she played the delicate strings. Source from 'Xianghe Ci: Ziye Jing Ge Er Shou Er'.
朱: Vermilion, a deep red hue; the name of a mineral; an ancient geographical location; and a surname.
口: Oral cavity, harbor.
Meaning: Vermilion lips symbolize a beautiful and melodious voice, describing a captivating and pleasant sound.