The term "cut sleeve" is a traditional Chinese euphemism for homosexuality. It originates from a famous legend of tender affection and same-sex love between Emperor Ai of the Han Dynasty and his male lover, Dong Xian.
Around 10 BCE, during the Eastern Han Dynasty, Emperor Ai and his court official Dong Xian were napping together during the afternoon. When the Emperor woke up to attend to court duties, he found that Dong Xian was fast asleep with his head resting directly on the Emperor’s long silk sleeve.
Rather than disturb his lover by waking him up or pulling his arm out, Emperor Ai took a knife and sliced off his own sleeve. This single act of gentle devotion inspired the Chinese idiom "the passion of the cut sleeve".
The idiom has become a broadly recognized euphemism for male same-sex love in Chinese culture. It is an archaic, literary, and poetic term rather than a derogatory slur, frequently encountered in historical texts, folklore, and modern fictional genres like danmei (Chinese queer media).
In the context of ancient Chinese culture, the term belongs to a duo of romantic idioms. The other famous equivalent is "the bitten peach", which originates from a story about Duke Ling of Wei, who shared a notably sweet, partially eaten peach with his male lover to show his affection.