The British Idiom – Suck eggs
Definition of Suck eggs
The expression, to teach your grandmother to suck eggs, means to try to tell somebody who has more knowledge and experience than you how to do something.
Examples of Usage of Suck eggs
You’re trying to tell me how to take a photograph? I was taking photographs when you was still a fetus. Don’t teach grandmother how to suck eggs. Trying to tell him how to ride a motorcycle was like trying to teach your grandmother to suck eggs.
Now watch my YouTube video English lesson which contains this British English idiom.