Posted on November 12, 2016June 3, 2021 by Idioms Poster Teaching a dog to suck eggs Mix up of:Teaching an old dog new tricks, andTeaching you to suck eggs.From Trey, swimming teacher, Crouch End, London, UK.Related IdiomsReal idiom: You can’t teach an old dog new tricksReal idiom: Teaching (your) grandmother to suck eggs Post navigationPrevious post: Trial by errorNext post: A Spaniard in the works