F,
I was not taught in the services and would obviously not dare to question Thom's so if that is what they call the simultaneous movement around the three axis on spin entry so be it.
Fact is though that if you go too slow in a slip you will NOT spin.
If you go too slow the high wing will stall first and if you whilst this is happening reverse the inputs (as in rudder and aileron) you will end up in a sideslip opposite to the one you started with.
You can repeat this infinitum (obviously height permitting)
FD