Wiktionary
in one's pocket
a. (context idiomatic English) Subject to one's whims because of bribery.
Usage examples of "in one's pocket".
I am no more greedy than the next man, but gold, whether in the form of the legends of Golconda and the 'Forty-niners, or a sovereign piece to clink in one's pocket, has always fascinated me.
Credits in one's pocket are worth more than the credits that might be sprinkled someday over your grave.
And one is constantly obliged to keep one's hand in one's pocket there.
His particular skills could be useful things to have in one's pocket.