Who's in control?

So a friend was relaying a story about telling a workman that her brother-in-law liked to be in control. The workman said oh yes I know. Since the workman had barely spoken to her brother-in-law she wondered how? The workman said that when he went to shake hands he had reached out his hand palm down and covered his hand when they grasped. As opposed to meeting as equals with thumb up or friendly with palm slightly raised. 

As a woman I don't have as much experience of handshakes as I expect a man has, and frequently I think people temper their shake when they grip a woman's hand, so I'm fascinated by learning this new body-language... It's like secret coding.