Drifting 4WD is very similar to FF drifting as the front wheels are the power wheels, but in this case so are the rear ones. As you approach the turn use the "Feint" motion and lock up the rear wheels by using the handbrake (R2 by default) and turn into the turn. You will begin to slide around the turn, but once you rear the apex you will most likely need to pick up some more speed. Release the handbrake then get back on it when the angle starts to decrease, and you will have more speed to complete the turn. Depending on the turn you may or may not have to turn into it the whole time. Many turns can be taken with "zero countersteer" meaning that you just use throttle control to keep the car drifting. On some turns it is easier to use the regular brake along with the handbrake while turning into the corner, then get off the regular brake and then drift it like a FF car from there.