Instructional Technique
We were doing spinning in a JP4. The first action for spin recovery was to check the turn needle before applying opposite rudder (copes with the inverted spin case). On the fifth very good recovery when the student had yet again not done that, I leant over, and jabbing the T&S at every word said "Look at the f***ing turn needle" At this point the glass broke jamming the needle hard over. He never forgot again. Not an approved CFS IT method.