My Son is high-functioning autistic. When he was a baby/toddler, we learned he had "sensory stimulation" issues. Nothing would keep him from crying for hours on end and the doctors couldn't figure out why. Test after test revealed nothing physically wrong. Holding/hugging only made matters worse and we were going out of our minds trying to find a way to comfort him. Advice we got was to remove clothing/blankets and other items that touched him whenever possible, which seemed reasonable but didn't work.
After reading one of Temple Grandin's articles, we decided to try a method she suggested. We began using what amounted to a huge ace bandage to "swaddle" him tightly. It worked like flipping a switch to turn off his crying and he was calm, happy and often asleep within minutes. A minor miracle for our family.
When he got older, up until he was about 10, he loved to sit on my lap and have me lock my arms around him from behind and squeeze as tight as I could for as long as he could take it; always saying "tighter, Dad, tighter!"
Today at 14, he's too cool to sit on Dad's lap anymore but still has to have tight-fitting clothes/shoes to feel comfortable.
So I guess there's something to it.