I'm gonna grave dig this thread as I am having a similar issue. As I've been gearing up for my '17 AT thru, I've been sleeping more regularly on my Xtherm. It is a MAX in large, so it is pretty wide for a sleeping pad. However, the only time I can comfortably sleep is on my back with my arms to my side. When I try to sleep on my sides, the arm I am sleeping on almost always ends up going numb and tingly. When I sleep on my stomach, I usually put my arms over my head, and that also ends up with them going to sleep. Anyone have any solutions to this? Or should I just stick to back sleeping when in my tent.