know which side (one's) bread is buttered (on)

To know how to best ensure one's success. I know which side my bread is buttered on, so I was very nice to the recruiter and promptly sent her a thank you card after our interview.

know which side one's bread is buttered on

Prov. to be aware of where your money comes from; to be loyal to the person or thing that will benefit you the most. Wife: Please be sure not to upset Grandma. You know we can't do without the money she sends us every month. Husband: Don't worry. I know which side my bread is buttered on.

know which side your bread is buttered

If you know which side your bread is buttered, you know what to do or who to please in order to put yourself in the best possible situation. Donald was a man who knew with utter clarity which side his bread was buttered. I'm in no doubt which side my bread is buttered for the present.

know on which side your bread is buttered

know where your advantage lies.

know which side your ˈbread is buttered

(informal) know what to do in order to gain advantages, stay in a favourable situation, etc: I’m sure Ray will make a special effort to please the new supervisor — after all, he knows which side his bread is buttered!