I don't think hugging your pillow is an AS trait. I think it is just a preference, the same as a person having a preference for sleeping on their back versus side, or stomach. Covering yourself in heavy blankets, however, unless it is a cold night, provides pressure on the body that is comforting to many people on the spectrum.
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"At times our own light goes out and is rekindled by a spark from another person. Each of us has cause to think with deep gratitude of those who have lighted the flame within us." - Albert Schweitzer