That would be clutch kick, but remember to gracefully and effeciently accomplish clutch kick, you have to not only quickly release the clutch (done by sidestepping) you have to rapidly depress the clutch, this is what causes the pre-staging, so to speak, for the clutch kick. It unloads pretty much all pressure from the rear wheels and allows the engine RPMS to shoot up. Once you sidestep the clutch is engaged and the wheels can break traction.
Rules of thumb with clutch kick. 3 is your number. You wanna drop your rpms to that number or with in that rpm range. Just to play it safe.
C.T.G, Clutch Turn Gas, That's the order, depress the clutch while turning (it should be near simultaineous) once you hear that little chirp of excitement from the rear wheels, mash the gas and sidestep. Have fun.
If you can't tell, clutch kick was my favorite technique that I learned, and it's still my most preferred.
I've learned how to initiate a simulated clutch kick in GT3.
While holding the gas, depress the reverse button. The RPMS will SINK and your traction will be nill. But the cool thing is your rear wheels wont lock.
That's clutch kick.
And for some added fun, allow your reverse gear to engage while drifting in GT3. You'll hold a drift deeper and longer than you ever thought you could.
Keep in mind that for all of you actual drifters out there, I would NOT try this in a real car, for fear that my transmission would fall on the floor.
Have fun and stay sideways.