That's when a man whose hand has been amputated feels as if his hand exists and performs functions as if his hand (the absent one) still exists.
Now here this: there's something called the phantom phone hand. Fast company has this article on this phenomenon.
That's when we reach out to our mobile phone to check a short message or email when it is not there. I have seen plenty of such weirdos in the train, constantly checking their phones, talking continuously, not being able to control their impulses.
Must say I have felt it too. But I have fought this urge with all my will. Nowadays, I ignore my phone and don't answer calls if it is after 9.30 p.m. I guess nobody has the right to disturb my privacy after that time. Unless of course it is a close friend or family. I think we must draw the line somewhere.