Lily's kiss brought a small smile to Severus' face, at least she did not get angry at him for kissing her. He squeezed her hand a little afraid that if he let go all this would turn out to be a dream. He didn't want this to be a dream, he wanted this to be real and Harry be a figment of their imagination.
He didn't want to say something stupid, but he also knew saying nothing was not good either. "I hope you didn't mind..." He trailed off, looked at Lily's lips for a moment again with a blush on his face.