Shuĭ kǒu luósī (-)
original: 水口螺丝
device used to drain saliva from the air chamber of a mouth organ with a circular (cup/bowl-shaped) wind chest
Literal translation: 水: "water"; 口: "opening", "hole"; 螺丝: "screw"; Bolt [the Chinese of which is actually 螺栓 (luóshuān)] in the wall of the cup of the Yuán shēng, used to drain saliva from the Qì qiāng (air chamber).
汉英词典 (Hàn Yīng cídiǎn) / A Chinese-English dictionary. 北京 [Běijīng], 1985, p.641, 393 (口 ➁, ➃) & 450.