ape (someone's) behavior
To mimic the behavior of someone, generally in a mocking or derisive manner. It is pretty standard now for comedians to ape the president's behavior and manner of speech.
be on (one's) good behavior
To be very polite or exercising exceptionally good manners. Primarily heard in US. Now, you kids must be on your good behavior for your Auntie this weekend! Good morning, class. I hope everyone was on their good behavior for the substitute teacher yesterday.
be on (one's) best behavior
To be very polite or exercise exceptionally good manners. Primarily heard in US. Now, you kids must be on your best behavior for your Auntie this weekend! Good morning, class. I hope everyone was on their best behavior for the substitute teacher yesterday.
on (one's) good behavior
Being very polite or exercising exceptionally good manners. Primarily heard in US. Now, you kids must be on your good behavior for your Auntie this weekend! Good morning, class. I hope everyone was on their good behavior for the substitute teacher yesterday.