In the Warring States Period, the State of Qin besieged¹（被包围，被困扰） the capital of the State of Zhao. Duke Pingyuan of Zhao planned to ask the ruler of the State of Chu personally for assistance. He wanted to select a capable man to go with him. A man called Mao Sui volunteered. When the negoti-actions between the two states were stalled（失速的） because the ruler of Chu hesitated to send troops, Mao Sui approached him, brandishing²（挥舞，炫耀） a sword. At that, the ruler of Chu agreed to help Zhao, against Qin.

This idiom means to recommend oneself.