"Hang a moxa stick" is a phrase that refers to the traditional Chinese medical treatment of moxibustion, in which a stick or cone made of the herb mugwort (艾草, "ai cao" in Chinese) is burned near or on the skin to stimulate acupuncture points or areas of the body believed to be deficient in qi (气, a concept in traditional Chinese medicine that refers to the body's vital energy).
The phrase "hang a moxa stick" likely comes from the practice of hanging the moxa stick over the skin or acupuncture point, rather than placing it directly on the skin. This is often done with the use of a special tool called a moxa roller or moxa box, which allows the practitioner to hold the moxa stick at a distance from the skin while it burns.
Here are some example sentences in English that use the phrase "hang a moxa stick," along with their translations in Chinese:
"I had to go to the acupuncturist for a moxibustion treatment because I had a cold. They hung a moxa stick over my toes and it really helped clear my sinuses." (我因为感冒去看了针灸师，他们在我的脚趾上挂艾草，真的帮助了清除我的鼻窦。)
"My grandmother always swore by moxibustion for relieving pain and increasing circulation. She would hang a moxa stick over her lower back whenever she had a muscle spasm." (我的奶奶总是坚信艾灸可以缓解疼痛和促进血液循环。每当她肌肉痉挛时，她都会在腰部挂艾草。)
"I've heard that moxibustion can be used to treat a variety of conditions, including digestive issues, asthma, and even infertility. I might try hanging a moxa stick over my stomach next time I have indigestion." (我听说艾灸可以治疗各种疾病，包括消化问题、哮喘甚至不孕不育。下次我消化不良时，我可能会尝试在肚子上挂艾草。)