According to dictionary, the general meaning of these words (wheedle, cajole and coax) is : Influence or urge by gentle urging, caressing, or flattering. But I am confused regarding the usage of these words. For what type of persuasion each word can be used ? What is the real difference between them ?

According to dictionary, the general meaning of these words (wheedle, cajole and coax) is : Influence or urge by gentle urging, caressing, or flattering.

But I am confused regarding the usage of these words. For what type of persuasion each word can be used ? What is the real difference between them ?