As stated in the previous response adverse yaw is caused by the downgoing aileron creating more drag than the upgoing one, causing you to yaw away from the direction of the turn.
The C152 has what are known as frise ailerons. The ailerons are hinged so that the leading egde of the upgoing one will protrude into the airflow on the bottom surface of the wing, thus creating drag to counter the drag created by the downgoing aileron.
The Tiger Moth has a system (dont know what it is called) where the downgoing aileron reaches its most displaced point at about 3/4 of control stick travel. If you move the control stick more the upgoing one keeps going up, but the downgoing one will also start to come back up. The theory here is to limit the adverse yaw when it would be at its worst, that is at full control deflection.
Hope that helps!