twist/wind around one's little finger, to

Fig. to manipulate and control someone. Bob really fell for Jane. She can twist him around her little finger. Billy's mother has wound him around her little finger. He's very dependent on her.

To exert a strong influence or complete control (on or over someone). This hyperbole dates from the nineteenth century. J. L. Motley used it in Rise of the Dutch Republic (1855): “She had already turned that functionary around her finger.” A more violent twentieth-century locution is to twist someone’s arm, a form of none too gentle persuasion. However, it often is used jocularly, as in, “You twisted my arm,” meaning either “You talked me into it” or “I don’t need to be persuaded to do this; I’d do it anyway.”