得便宜卖乖

得便宜卖乖

Literally means:

pretend to behave graciously after obtaining gains; swagger and brag after having gained some advantages.

Actually means:

卖乖 means showing off or displaying one's cleverness.

The phrase means one shows off his cleverness after gaining advantages by saying something to trick the person who should have been thanked into thanking him.

It often displeases the listener. Sometimes it is used as a joke. It carries a sense of derogatory.

卖乖，卖弄聪明，显示乖巧。得便宜卖乖，得到了便宜后不但不感谢对方，反而耍小聪明说些要对方感谢他的话。

多让对方不高兴。有时也用于开玩笑。具有贬义色彩。