I guess I am already in stage 3, because my soft palate is tight enough, that it throws my tongue all the way up into the top half of the nasal septum LOL
I am trying to do kechari mudra, just while sitting in a chair.
I collect and spit out all the salty secretions, because thats what I read in Mallinson's book.
I find an additional benefit in the internal kumbhaka aspect...hopefully I can see the famous AYP star soon.
These stages are just a way to gauge progress. Once you are able to practice kechari, the next real step is comfort and ease so that it becomes second nature. Once that is achieved it is no big deal, just one of your tools in practice.