Jacky is itdy but I barely mention that Herman is GiGaNtiC. His human (canon) design is 6'5 to 6'7.
People also still think Herman's dragon form is made of yarn. It's made of meat. Lol

I picture the yarn coming off a bracelet on his wrist. Canonically it would come out of his puppet, which is usually the human form, but the dragon is pretty much always a meat AU now.