I have had a friend come with me once. It was when I had a consult with a Emdr T once (not the one I see). I was REALLY nervous. So Bff offered to go with me and then go to lunch. She planned to sit in the waiting room. The T offers for her to join us. We both declined. It was helpful in that the T was super weird. BFF discouraged me from returning even though I was trying to convince myself that I should give her a break.