teach (one's) grandmother to suck eggs

(redirected from teach your grandmother to suck eggs)

teach (one's) grandmother to suck eggs

To try to teach an older person who is wiser and more experienced and wordly than a young person may think. Why are you explaining basic typing to Ethel? Yes, she's 70, but she's been using a computer since before you were born—quit teaching your grandmother to suck eggs.
See also: egg, grandmother, suck, teach