I do the curl up and shake thing a lot. It's actually why I chose my username
I didn't really think about it, but I go mute, or mute-ish, often too. It's like I'm trying to force words out of my mouth and making strangled choking sounds.
I've cried a couple of times. I know I block myself, I can feel it, but I can't entirely stop the block for whatever reason. Apparently I've trained myself to laugh whenever I'm in danger of crying too much. A few times I've cried while laughing. You know how people say 'laugh through your tears'...? With me it's more like cry through my laughter...