Learn English – An idiom for encouraging sucking up

phrase-request

How can I encourage a person to suck up even to the meanest of people, when doing so would benefit the person sucking up? In Arabic, an expression draws this image:

If a dog has something you need, address it as 'master'.

Unlike in western cultures, dogs are generally and sadly undesirable things here, which explains why dog is used as a swear word.

I'm not looking for an English expression that exactly mirrors this, but the closer the better.

Here's an example of how I intend to use the English expression:

Husband: My stupid manager has declined my request for a pay rise. I've been working with him for over 10 years. I know he doesn't like me because I don't suck up to him like everyone else. A new hire gets paid more than I do. Would you believe that?!

Wife: …..

Best Answer

One possibility is:

You should know which side your bread is buttered on.

It doesn't go as far as to advise outright ass-kissing, but it does advise to be aware that you need to remain in the good graces of someone who has such power over your life.