have (someone) in (one's) hip pocket

To have someone under one's control or influence, especially in an underhanded or unethical way, such as by bribery or extortion. It's pretty obvious that corporate bigwigs have all of our national legislators in their hip pockets. I hear that the boss has half the police force in his hip pocket. A: "What exactly are you suggesting? That the mob has me in their hip pocket?" B: "Well, it just strikes me as odd that you're no longer going to testify against them."