undy,
When you are at or near the fore-and-aft traction limit for the rear tires, any 'celeration (ac- or de-) will upset the car and cause a spin.
Example: a downshift while the engine speed is effectively slower than the tire speed will cause "TTO" (trailing throttle oversteer), which means you have just induced the snap-spin Cobras are so noted for. Under some conditions, just lifting the right foot suddenly can cause the same behavior! Acceleration can also create the same result.
Most driving schools will have you do this on purpose very early in their exercises so you'll know what causes it, and then later, how to correct if your reflexes are quick enough, you have enough room, and your rabbit's foot is working perfectly.
Most of the time it is better to put "both feet in when in a spin" so the engine can't cause any more problems, and the car can get stopped in as short a distance as possible.
Glad your end result is benign. Many have suffered much worse!
Get the car repaired thoroughly and then try a driving school
You'll have fun and possibly prevent a recurrence.
Tom