Also, unlubricated condoms. Steady...
They are great (I hear) for carrying water in a pinch.
I just Google'd it (I wanted to remember where I picked up the idea), and although I couldn't find anything I had seen before, the following two links have some good ideas:
http://willowhavenoutdoor.com/featur...-for-a-condom/
http://www.themodernsurvivalist.com/archives/2076