What does it mean to lie to a copper coin?

Belonging to dragons: illusory plays and empty words

Dragon people are good at pretending to be poor. Once something goes against their wishes or what they want, they will pretend to be poor. Wagging his tail and begging others to give him this chance. After getting this opportunity, he once disdained to give it to others, or advertised everywhere that he didn't care about this opportunity at all.