One of the "habits" I got into when I was growing up and sleeping in a single bed was the idea of cocooning myself using my doona or eiderdown. The idea was that you lie down, rock over to one side (so that the blanket falls underneath you, then rock over to the other side (so the blanket gets stuck under there and finally lift your feet so that the blanket covers your feet and you can't move. It was also not uncommon to have the blanket pre-filled with stuffed animals.
When I got older and moved out of home - and even got married, these behaviors persisted (not the stuffed animals part of course) despite my wife's clear dislike of the idea. I've tried to keep the blankets "normal" but I don't sleep as well. It's only relatively recently that I've realized that this is pretty much an Asperger's behavior.
I can't say for certain that this is common to all people with Asperger's syndrome but I've heard it from enough people to feel that it probably is the case;
Light touch is really annoying. If someone brushes against me, I can find myself scratching for hours. The feeling of being touched simply doesn't go away.
In the early parts of our marriage, my wife used to wake me sometimes by tickling my feet. It always provoked a negative reaction and I'd jump from the bed and start trying to scratch my feet on carpet, steps etc. It was a terrible way to wake up. Being cocooned however, prevents accidental light touches.
Self touch is bad too. I can't sleep if one of my body parts is touching another. The same goes for my own breath on a body part. I have to cover my arms to make sure that I don't blow on them.
I can usually sleep with my arms by my side but I can't sleep with my hand touching my face or neck. Sometimes this happens when I'm asleep and sometimes I put my hands under the pillow so that they won't move. Again cocooning solves this problem because it makes your body act as one. It keeps everything together and stops your limbs from moving.
Finally, Hugs are good. I've spoken to many people on the autism spectrum and the majority of them seem to be saying that while light touches are terrible, tight hugs are very soothing. Cocooning is like having a tight hug all night long.
Even in summer, I can't sleep without something on me. In summer though, I swap the blanket for a tightly wrapped sheet.
Are Blankets Better than a Partner?
The whole cocooning thing really annoyed my wife in those early years of marriage and I had to try things "her way" for many years. As a result, I had big sleep issues during those years. In the end though, I found myself waiting until she fell asleep and then using an extra blanket for the cocooning (and ditching it in the morning).
I was often asked why I needed to cocoon when my wife was in the bed with me and I can understand how it must seem. I can remember being a teenager and thinking how great it would be when I was married because I could just sleep in someone's embrace all night long. The reality of it all though is that this is hot and uncomfortable. The other person's movements disturb you and their breath and snoring can keep you awake all night long.
It's nothing to do with intimacy though and everything to do with touch.
So, if your partner with Asperger's syndrome makes a cocoon, don't take it personally. It's just the way that he or she likes to sleep. It doesn't mean that they don't want to be intimate, simply that they want to ensure that they have a good night's sleep.