ever seen jet li's tai chi master? theres one segment of the last fight scene where jet performs snake creep down as a low evasion, then follows forward and using the kao or bump slams his shoulder area into the groin of his opponent, of course, jet bumps the guy half way across the planet, but that app is definately right there...cool too...
shaoming cheng, who teaches BaGua and Tai chi in Athens, Ga taught us that the creep down could be used as a 'jam' for defending a chin na on the forward wrist...ever play Da Lu???
when performing needle at sea bottom, think chin na as well...
in this beginners opinion, and to concur w/ chufeng, most (if not all) of the postures have loads of applications for controlling, evading, striking, or even just plain getting away...