[demick]

You are driving a rear wheel drive car with a decent amount of power. If you apply too much power during a turn, you can break the rear tires loose and lose traction. When this happens, the back end will step out. If you don't know how to correct for it, the rear end will come around and you will spin out, which is what happened to you.

As BYprodriver said, time to learn some car control.