I have only been training for a little while, so I'm still a white belt. But the other day we were rolling, and there weren't any people for me to partner up with so the instructor offered to roll with me. I agreed expecting to get worked, but also to learn a lot. I was half right. We rolled for a bit, I was doing well, but still getting dominated. Anyway at one point the instructor was in my half guard, I have a pretty poor guard, so I was expecting him to pass easy. Instead he just locked both hands behind my head and cranked the shit out of my neck, I thought it was like a guard passing strategy, so I relaxed my legs completely so he could pass without any 'trouble'. It was hurting quite a bit at this point, but he just kept my chin pressed to my chest, while jerking my head side to side until I tapped. Not wanting to look like a bitch, I just got up and told him good job etc, etc. But my neck has been sore for about a week now, and I was wondering if this is common practice.