Good advice from those posting above. After you have accomplished rev matching, if you want to practice, may I suggest going to a full clover leaf at one of the interstates near you. You can practice to your hearts content, going around the clover leaf repeatedly, down shifting at high approach speeds as you approach the exit. Since the speed limit is around 65 - 70 mph, the HP will probably leave you alone. They may think you are crazy, going around in circles, but you are doing nothing illegal. Shifting away to some good music too.
vz