Yìngtǔ (-)
original: 硬吐
blowing techniques (SE Asian mouth organs): in-/exhaling
Literal translation: 硬: "hard", "strong / firm"; 吐: "(to) spit"; Defined by Wong as "[to play with] heavy breaths".
Wong, Samuel Shengmiao: Qi’ - An instrumental guide to the Chinese orchestra. Singapore, 2005, p.143.
汉英词典 (Hàn Yīng cídiǎn) / A Chinese-English dictionary. 北京 [Běijīng], 1985, p.833 (硬 ➀, ➁) & 696.