The Chinese idiom "拍马屁" (pāi mǎpì), literally meaning "to pat the horse's rear," originates from the social customs of the Yuan Dynasty, when inferiors would literally pat the rear of a superior's horse as an obsequious gesture to praise the quality of the steed and, by extension, flatter its owner. Over time, this literal action evolved into a fixed metaphorical phrase used exclusively to describe the act of fawning or giving insincere, exaggerated praise to curry favor with someone, completely shedding its original literal meaning to carry a strong negative connotation of sycophancy.