On flight tests you ask the candidate to demonstrate a stall. Invariably they close the throttle and make no attemt to compensate for the yaw caused by reducing the slipstream. Invariably, they apply some aileron to keep the wings level thus, if you hold the aircraft in the stall a wing is likely to drop.
As you approach the stall keep straight with rudder, never mind the ball, just look out of the window and pick a point in the distance. If you prevent yaw the wings will remain level until the aircraft stalls.