Sleeper Bus to Phnom Penh

First time to experience this, basically private little stalls, one upper and one lower running the length of the bus, with a curtain that doesn't quite close.  It is more like the 3rd class cars on the Trans-Siberian Express in Russia than a typical bus.  Enough room in our upper stall for the two of us to stretch out and lay down besides each other for the overnight drive.  Still, with the abysmal quality of the roads in Cambodia in certain patches, it felt like we would be shaken out of the stall and onto the narrow aisle.  And yet, it was much easier on our necks than being seated upright the entire night.