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 ...
As I tried to say before, our kihon waza of tanto dori / jo dori / tachi dori irimi nage ends with tori immobilizing uke by applying a choke. It is called "choke" because it is about interrupting uke's possibility to breathe. It is endet when uke taps out.
I wouldn't call this a pin? But it's clearly a form of katame waza just like the finalization of shiho nage or kote gaeshi can be.
Also there is a form of tachi waza irimi nage where uke is not thrown but choked, tori standing behind him. It can be applied as headlock, but also as choke. We do this very seldom. Here also: It is endet when uke taps out.
In both cases I don't know whether to call it 'formal'? It simply "exists".