at somebody's beck and call
at (one's) beck and call
Completely compliant or obedient to another person; catering to one's every need. The phrase has a negative connotation. Do you really think I'll do anything you say? I'm not at your beck and call! A: "How can we get to the mall this weekend?" B: "Oh, my sister will take us—she's been at my beck and call ever since I caught her sneaking in past curfew!"
at somebody’s ˌbeck and ˈcallalways ready and required to do exactly what somebody asks: Working in a big store means being at the customers’ beck and call all day.
Beck is a shortened form of the word ‘beckon’ (= give somebody a signal with your finger or hand, especially to tell them to come closer).