With his eyes intent on Harry's face, he's momentarily sidetracked. "God, Harry, you really need to smile more often," he paused, considering, then added, "well, only around me. You do it too often around others and I'll have to start fighting off rivals. Unless..."
It seemed the best segue, even if it had been unintentional. Still watching Harry closely, he continued, "unless this isn't an exclusive thing, you and me."