I have an adult relative who is a master at emotional blackmail with her older mother. If she squanders her own money and needs more, she won't hesitate to demand it from her mother. If her mother tries to refuse, she'll burst into tears and ask how a "good mother" could be so cruel. Her own flesh and blood is going to suffer because of a parent's stinginess. It's complete and utter emotional manipulation.
What's bad about emotional blackmail is that other people may be completely aware of it. The people in my office know that the receptionist's husband will get extremely upset if she doesn't come home directly after work. One day we all had to work overtime on a project and she couldn't leave at her usual time. Her husband called the main office line and screamed at me for keeping her out so late. The tone in his voice sounded like he was in real emotional pain.