http://knows.jongo.com/res/article/16538  
Dong Xian and Emperor Ai of Han
Of all the male favorites of the Han emperors, Dong Xian is probably the most well-known. The expression "a preference for the truncated sleeve" 断袖之癖, which is still used today as an euphemism for male homosexuality, originates from the story of Dong Xian and Emperor Ai.

Chapter 93 of The Book of Han: Record of those who obtain favor by skillful flattery

Dong Xian, whose moniker was Shengqing, was a native of Yunyang. His father Gong was an Imperial Investigative Officer. He gave Dong Xian the job of attendant to the Crown Prince (who would become Emperor Ai). When Emperor Ai ascended the throne, Xian remained in his entourage. A little more than two years later, he was making a report outside the palace hall – he was beautiful and narcissistic - when Emperor Ai saw him and remarked on his manners and looks. He recognized Dong Xian and asked, "Isn't this the attendant Dong Xianω" Dong Xian was summoned to speak with the Emperor, who made him an Official-in-waiting. This was the beginning of his favor.

The Emperor then asked after Dong Xian's father, and the next day he made him Mayor of Baling and 光禄大夫. Dong Xian's favor increased daily and he was made Manager of Horses for the Imperial Attendant Carriages. He often rode in the same carriage with the Emperor when the Emperor went out. In the palace, he was always around the Emperor. In the space of 10 days to a month, the Emperor had bestowed upon him riches worth many tens of thousands. His honor and power shook the entire court.

He was often with the Emperor, whether standing up or lying down. Once, Dong Xian was napping across the Emperor's sleeve. When the Emperor wanted to get up, Dong Xian was unaware. The Emperor did not want to disturb Xian, so he truncated his sleeve and rose up.