Agreed that the term is misleading, but that's what the BJJ people call it.
Nonetheless a good question Conrad. Personally I have used it in training more from the view of how to 'get out' of one rather than how to do one.
To do one would be as I described above but would enter a specific part of Aikido as far as I am concerned and that would be the area of pins. Now as far as I know there is no such 'formal' pin yet I see no reason that it couldn't be used in such a way but would take some expertise to do as such.
I would envision it to be like a headlock which is inescapable and immobilizing yet based on the principles of Aikido.
Anyway, I'm sure you'll get much other food for thought here.
Happy hunting. G.