in the palm of one's hand

have somebody in the palm of one's hand (to have control over somebody, to be able to persuade somebody to do things to your liking ) — веревки вить из кого-л.; иметь полную власть над кем-л.

Example: Once she began to tempt him with her beauty she soon had him in the palm of her hand.

Related vocabulary:
[wrap around one's finger]
[lead by the nose]
[веревки вить]
[держать на коротком поводке ]
feed sb out of one's hand
cf
eat out of sb's hand