I've only gone through it a couple of times, it feels so real though like you feel quite feral in thought and cannot really focus that well as your mind isn't used to the thoughts and desires of this form. You can often feel phantom influences like claws, tail, ears, and maybe fur or in the case of avians, wings and feathers or scales for reptiles. It's generally comfortable or not comfortable to all that experience it, no inbetween at least from what I have heard. When it happened to me I was in the middle of a computer lab and I just was not ready for it, my hands felt like they were on fire x.x