putty in somebody's hands

putty in (one's) hands

Easy to control or bend to one's wishes. (Putty is a very malleable material.) Oh, come on, Julia is putty in our hands—we can definitely get her to help us with this prank.
See also: hand, putty

(like) putty in somebody’s ˈhands

(informal) willing to do anything somebody wants or tells you to do: As soon as she starts crying, I’m putty in her hands. OPPOSITE: (as) stubborn as a mule
Putty is a soft flexible substance used for fixing glass in windows.
See also: hand, putty