I have never used a Nalgene, but my avalanche cords are all in small (brightly colored) bags -- one to find them in my pack and two so that I can put something in the bag, tie the cord to it and use it as described. Unfortunately I have had to do it too many times. A few (very few) in steep terrain. Spooky is the best word I can think of (thanks MostlyHarmless). Of course, you don't have to worry about immediate hypothermia - the sweat is comming fast. :0

Respectfully,

Jerry