I don't know if it's related to AS or not, but I seem to always have to sit in "weird" positions. I've done this ever since I was a child. When I sit in front of the computer, I often sit on my foot, or with the feet on the wall beside me (looks very strange, not gonna lie), or like L in Death Note (no, I did not obtain the behaviour from that show - when I watched it, I was like "wow! Another person that does it!") etc. Sometimes I twirl my legs around each other. I have this one position that I don't think I've ever seen anyone make, where I put the foot of leg 1 underneath the thigh of leg 2 and then put leg 2 over the knee of leg 1. VERY COMFORTABLE.
My mother often tells me to put my feet down when we're eating dinner - I tend to put my feet up on the chair. Not immediately, but maybe like 5-10 minutes into the dinner when I just can't stand it any longer. It's just uncomfortable to sit "normally". If I cross my legs, I often "sit like a guy" (as in not having the legs fully crossed but rather having one foot rested on the other knee), making me look not-at-all-feminine. If I am "forced" to sit normally, I tend to move around in my seat a lot. Does anyone else experience this?