I cannot sleep with any layer, very uncomfortable indeed. To be honest, I cannot stand the idea of getting irritated by clothing during my sleep. Not only that, even the faintest bit of light or even the slightest periodic ticking of the clock (or anything for that matter) annoys me. A thin blanket will do in the summer, but usually tucked to the side when hot, and a second blanket of the same material in the winter, a third blanket of the same material as a bed sheet. Everything needs to be dead quiet and super dark when I'm sleeping. I'm trying to achieve the darkness to the point where the capability of the human eye adaptation to low-level ambient light won't matter (absolute pitch black).