As part of the initial spin lesson I always demonstrate what other posters are calling "oscillatory stalls". That is smoothly apply full back stick just prior to the stall and then after the aircraft stalls keep the full back stick applied.
The purpose of this is to demonstrate that if yaw is controlled the aircraft will not spin even if it is stalled and the primary anti yaw control is the rudder. For non aerobatic instruction (ie the PPL/CPL) the emphasis should not be on how to spin an aircraft, it should be on how Not to spin an aircraft. Critical to that IMO is to make sure that in the event of an inadvertent stall yaw is instinctively prevented as the nose is lowered to reduce the AOA and power applied. Again this manoever is demonstrated once by me and is not a student solo exerecise.
I also use this exercise when teaching the spin for the aerobatic course but in this case for entirely different reasons. For aerobatics, spins are both a deliberate manoever and the likely result of a botched manoever so the student needs to have a very good understanding of the effects of controls when the aircraft is stalled and when and how yaw can/should be controlled.