Snape sighed through a throat gone suddenly tight. At this moment he felt a pure, simple happiness that took him utterly by surprise and left him in a rare state of speechlessness. By way of reply, he leaned his head toward that whispering mouth, offering the ear still hidden behind a thick fall of hair.
He didn't tuck his hair out of the way behind an ear. Instinctively, his hands continued to clutch the shelves to either side of Al's head: he was so lightheaded that he felt instinctively that if he took his hands away from that support, he'd fall forward, plummet into eyes as green as an AK: the death of the last shreds of his common sense.