<< I apologize if this shows up twice >>
Maytera Marble has cooling coils in her cheeks. Mucor's brain is so different from normal that it baffles a brain surgeon. Silk, like Mucor, is also the product of an altered embryo, so parts of his anatomy may be very different from normal. I think the description of Marble's coils may be intended to serve as a clue that Silk has some unique anatomical feature in his cheek. I've seen pointed out on the list that often Silk touches his cheek before making some kind of deductive leap. Possibly the circling motion of his fingers stimulates this effect, or the effect somehow prompts him to touch his cheek, like a mild itch.
Brian