Neville was holding his breath until Hannah had kissed him again on his forehead and slowly moved down his face. He finally exhaled when she spoke, biting his lip so he wouldn't interrupt... he wanted to hear every word. Just that she had missed him too made him feel like less of a clueless sod.
However, he then felt like a teenager when he heard the creak of the stairs... being caught by a teenager. Neville instantly knew that his son was standing on the stairs behind him. Normally, catching one's parents in that kind of situation would be gross to a young man, this though, this was probably much too confusing.