Yep. It is a raport building technique used to help you feel more comfortable. There are all kinds of mirroring and it doesn't just happen in therapy. The person just does something the same way you are. They may talk at the same pace, sit in the same position oh so many ways. In frienships it can just happen naturally. Ever been shopping or walking with a friend and you realize that you are both stepping with the same foot at the same time? That is when it just unconsciously happens. My T does some of it consciously and some of it unconsciously too. Some times when we get that feeling that we have done something wrong or that someone is no longer listening but can't put our finger on why, it can because the mirroring was interrupted.