What is countersteering?

A Turning the wheel back in the other direction after steering to avoid a hazard

explanation

Be prepared to "countersteer," that is, to turn the wheel back in the other direction, once you've passed whatever was in your path. Unless you are prepared to countersteer, you won't be able to do it quickly enough. You should think of emergency steering and countersteering as two parts of one driving action. [Commercial Driver Handbook]