A spin is an aggravated stall resulting in rotation about the center of gravity wherein the aircraft follows a downward corkscrew path. Spins can be entered unintentionally or intentionally, from any flight attitude and from practically any airspeed—all that is required is sufficient yaw at the moment an aircraft stalls. An incipient spin is typically driven by inputs made and held by the pilot, whereas a fully developed spin is a self-sustaining maneuver. In either case, however, a specific and often counterintuitive set of actions may be needed to effect recovery. If the aircraft exceeds published limitations regarding spins, or is loaded improperly, or if the pilot uses incorrect technique to recover, the spin can lead to a fatal crash.
In a spin, one wing is sufficiently stalled and generates significant drag but little or no lift, and the other is either not stalled or not stalled as fully as the other, and generates significant lift. This causes the aircraft to autorotate due to the non-symmetric lift and drag. Spins are characterized by high angle of attack, low airspeed, and high rate of descent.
Spins differ from spiral dives which are characterized by low angle of attack and high airspeed. A spiral dive is not a type of stall because the wing is not stalled and the airplane will respond to the pilot's inputs to the flight controls.
Taken from Wikipedia
The Cessna 152 POH indicates the recovery procedure:
Should an inadvertent spin occur, the following recovery procedure should be used:
1. PLACE AILERONS IN NEUTRAL POSITION.
2. RETARD THROTTLE TO IDLE POSITION.
3. APPLY AND HOLD FULL RUDDER OPPOSITE TO THE DIRECTION OF ROTATION.
4. JUST AFTER THE RUDDER REACHES THE STOP, MOVE THE CONTROL WHEEL BRISKLY FORWARD FAR ENOUGH TO BREAK THE STALL. Full down elevator may be required at aft center of gravity loadings to assure optimum recoveries.
5. HOLD THESE CONTROL INPUTS UNTIL ROTATION STOPS. Premature relaxation of the control inputs may extend the recovery.
6. AS ROTATION STOPS, NEUTRALIZE RUDDER, AND MAKE A SMOOTH RECOVERY FROM THE RESULTING DIVE.
If disorientation precludes a visual determination of the direction of rotation, the symbolic airplane in the turn coordinator may be referred to for this information.
Intentional spins are approved in this airplane. Before attempting to perform spins, however, several items should be carefully considered to assure a safe flight. No spins should be attempted without first having received dual instruction in both spin entries and spin recoveries from a qualified instructor who is familiar with the spin characteristics of the Cessna 152.
The cabin should be clean and all loose equipment (including the microphone) should be stowed. For a solo flight in which spins will be conducted, the copilot's seat belt and shoulder harness should be secured. Spins with baggage loadings or occupied child's seat are not approved.
Intentional spins with flaps extended are prohibited, since the high speeds which may occur during recovery are potentially damaging to the flap/wing structure.