They were playing around with various resistors while I poked at the oscilloscope and babbled at them when another student walked in from the adjacent lab. Tall&Oblivious was carrying an infrared temperature sensor. He told one of my students, whom I shall call The Blond One, to stand up.
The Blond One stood up. Tall&Oblivious pointed the sensor at his head and then at his crotch.
"There's a six-degree temperature difference between your brain and your cock," he concluded.
"Ahem," I said.
Tall&Oblivious started, as if he'd only just seen me. Which was, in fact, the case. The Blond One, who was now an interesting shade of magenta, began scrabbling through a box of components.
"That's exactly the information he always needed," I said. "Now shoo!"