all this was on an ASK 13, which does very nice spins. Of course
this junk was rationalized with a large infusion of crappy theories
about adverse yaw or whatever, when it is very clear that flying

I've heard a similiar theory: When flying along a ridge, always keep the
glider slightly slipping (keep the wing which points to the ridge
slightly leading), because like this, if you happen to fall in a spin,
it will turn away from the ridge...

As the instructor was in his seventies, I decided it wasn't worth a dispute.