Have a sympathy click
I had a similar experience in China myself. The bus was so full that there were people packed in the aisles as well.

I learned the best way to reduce the feeling of needing to shit was to lie flat on your back. This was a bit tricky for me because I was too tall for my bunk. Also, lying on your back means you miss out on the scenery, but it was all desert anyway.

Apparently, if you take the Chinese Sleeper Bus to Tibet, you have all the same problems but have to suffer altitude-sickness on top of it.
( mistaspakkaman and the inedible shifting caterpillars, Thu 3 Apr 2008, 12:35, Reply)