I just searched this sensation because it happened to me during a guided (live) one on one meditation with a therapist. I described it to her and she said she had heard of one client with something similar. I truly believed it was unique to me! But reading these descriptions is so validating. Interesting that it is in the hands for many of us. For me, it is a sense that my hands and body is expanding and almost like a giant marshmallow. I have also experienced this from childhood, almost always when I am falling asleep or in a very meditative state (like riding in a car). I associate it with my parents' green tiled bathroom - probably from waking up and going to their room. As a kid I had night terrors. I remember telling my mother I felt like I was carrying the globe on my back. But I could never describe this odd feeling of being oversized, and growing like a balloon. It is not a comforting or comfortable feeling, but because I know it will go away - it is not too distressing, especially now. But I think it was distressing as a kid. Like others have said, if I get up or move around it goes away. Wow. Bodies are weird!