What do you understand by the expression “Thumbprints on his windpipes?”

Celebrities often feel that they have been made the beast of prey through interviews. Saul Bellow was interviewed on many occasions but he always felt uneasiness. Once he described interviews as being like thumbprints on his windpipe. He considered it as an assult on his person. It was because that the interviewer created too much tension and pressure to feel suffocated. He felt as if he had put his thumbprints on his windpipe.