He nodded and moved, hands still on the collar, and ah. There. The seam was very small, nearly impossible to either see or feel, and were he not an elf, Thranduil wondered how he would have managed. The problem was there didn't seem to be any form of clasp - Thranduil was beginning to wonder if it had not been molded around his son's neck. No matter. It could be removed, and if it had to be bent out of shape for that to happen, so be it. Thranduil began to attempt to pull it out of shape. He was strong, as were all elves, but it was harder when he needed to be sure not to strangle his son while he did so.