It is a driving technique first used by the Scandinavian rally drivers where one brakes hard and turns the wheel away from the upcoming corner and then turns into the corner to unsettle the rear end and causing oversteer ( the boot wanting to overtake the bonnet) and by throttle and steering adjustment round the corner at speed.
By doing this the skilled driver can adjust the cars attitude to suit the many different corners that may open up or tighten up
This is now one of the tricks in a drifters repertoire.