Buffeting is a high-frequency instability, caused by airflow separation or shock wave oscillations from one object striking another. It cause by a sudden impulse of load increasing. It is a random forced vibration.
Buffeting. An irregular oscillation of any portion of an aeroplane distinct from 'flutter', because it is produced and maintained by the eddying wake behind some other part of the aeroplane, ...
The pilot should start recovery when buffeting begins, by simultaneously lowering the miniature aircraft to the horizon (or as required in the AFM) on the attitude indicator and adding maximum allowable power.
Every aircraft has its own spin characteristics, but most will go through an early incipient spin where rate of roll and yaw are fluctuating and the pilot may feel some airframe buffeting.
Do everything gently and stay relaxed. Keep one eye on the air speed and the other on the ball (or horizon and wing tips). Notice everything: buffeting, stick back pressure, control stops, "oil canning" or other noises....
See also: Buffet, Speed, Flight, Aircraft, Lift