I've been in full Kechari for about 2 and a half weeks now. What I've been finding is that in the very earliest days I could stay in for long because the entire pharynx became quite tender. When it gets tender like that, the thin mucus layer on it seems to start to become more viscous and eventually so much so that the tongue will not slip on it it -- I believe this is the 'dry' pharynx of which Yogani speaks in the lessons.
But over the course of the few weeks, it has become less tender over time and I'm finding that my tongue is able to spend more or more time in there. My max was about 20 minutes per day in the very early days, now it is more than an hour. I think eventually, there will be no limit; my pharynx will adapt, kind of like the eyes gradually adapt to a hard contact lens.
I'm wondering if the others who have reached full Kechari have had a similar experience?
-David