As it stands, I'm the only one I know personally who can do this. Everyone else I ask can replicate the feeling but not the visual effects of the task. Infact there is a bigger group of unhelpful people who want to tell me what I'm doing and they aren't even capable of replicating the feeling (according to what they tell me). Essentially what I can do is turn my arm/hand purple by choice. While nothing is actively cutting off circulation. I do this by deciding that's what will happen and it does. I do not know why I can, nor how I can. Infact I'm posting on here to find out if anyone else can do this or has any idea what this may be a door to? If anyone has any idea I would appreciate the input.