Ah Snake! You should've come with us in high school. Our local cave took about 3 hours to crawl into. At one point, we named "cork screw", you had to rotate 360 degrees as you progressed your body length thru it and at no time while 'doing the twist' could you get more than about 1/4 of a breath in without locking up tight in that spot.
Oh and on the way out it was confusing at one juncture so you'd continue for about 10 minutes before hitting a dead-end - always good for a quick adrenaline spike.
