During the Spring and Autumn period, a flattering Song official named Cao Shang was sent as an envoy to the Qin state. Upon arriving, he showered King Hui of Qin with sycophantic praise, winning the king's favor so completely that the delighted monarch bestowed upon him one hundred war chariots as a gift.
After returning to the Song state, Cao Shang was brimming with smug satisfaction, feeling utterly elated and losing all sense of proportion.
Once, he met Zhuangzi, the founder of Daoism, and boasted to him, "In the past, my family was very poor, and for a time I even had to make straw sandals to survive, starving until I was gaunt and sallow. Now, I suddenly possess a hundred war chariots of immense value—how proud this makes me!"
Zhuangzi looked down on Cao Shang, sneered coldly, and said, "Have you heard in Qin about hiring a doctor to suck boils and lick hemorrhoids?" Cao Shang, unaware of Zhuangzi's intent, shook his head and replied, "No! When I was in Qin, I never heard that King Hui of Qin had boils or hemorrhoids!"
Zhuangzi gave a cold laugh and said, "You are so ignorant! I've heard that King Hui of Qin once had both a carbuncle and hemorrhoids. He summoned his physicians and declared that whoever could suck the pus from his carbuncle with their mouth would be rewarded with a chariot, and whoever could lick his hemorrhoids with their tongue would be rewarded with five chariots. So it's clear that what you did in Qin was even more despicable and shameless than sucking pus and licking hemorrhoids, which is why King Hui rewarded you with a hundred chariots. What is there for you to be proud of?"
Cao Shang, upon hearing this, blushed with shame and slunk away. Later, the idiom "sucking boils and licking hemorrhoids" came to describe the despicable behavior of sycophants currying favor with the powerful.
Source: *Zhuangzi*, "Lie Yukou"
Meaning of the Idiom: Later, the Chinese idiom "吮痈舐痔" came to describe how the despicable behavior of sycophants currying favor with the powerful.