周瑜打黃蓋——一個願打，一個願挨

Etymology
A xiehouyu from the .

wanted, his subordinate, to pretend to defect to 's side so that Huang Gai could gain Cao Cao's trust. This allowed Huang Gai to set fire to Cao Cao's fleet during the, forcing Cao Cao to retreat. Zhou Yu had Huang Gai flogged in front of Cao Cao's spies so that they would not be suspicious.

Idiom

 * 1)  one is willing to give a beating, and one is willing to take a beating
 * 2)  both parties agree of free will, mutual consent; to willingly submit to something