"I place the exhaust pipe on his head?"
Since this text is a question and doesn't provide specific details, we could interpret it as follows:
"I place a chrome motorcycle exhaust pipe on a man's head. He has short, curly hair and wears a confused expression on his mildly bearded face. His wide eyes are light green. He is outside, under the clear blue sky. In the background, there's a red motorcycle with black leather seats parked on a gravel road."
