Fudge
"How can you eat that stuff, Severus? It's vile. Once you close your teeth to chew it, you can't open them again for the next two weeks."
"Oh, do be quiet. It's better than that foul stuff you eat."
Severus Snape sat comfortably in a great arm chair beside the crackling fire. It was dark outside and the castle was almost empty, as most students had gone home to enjoy the Christmas holiday with their family. He, however, was stuck with Remus Lupin for a couple of weeks. Three days in, and, although he was reluctant to admit it, it hadn't gone as bad as he had expected. He was rather enjoying the company of the defence against the dark arts teacher, even if he did have terrible taste in sweet food. Smiling and sighing softly, Severus leaned back in his chair and closed his eyes. Perhaps this would provide a good distraction from the fact that students would soon be returning and would give him more ghastly work to mark. He was genuinely looking forward to spending time with Remus. The idea of this made him a little nervous, as was to be expected. Snape opened his eyes to find the man gazing at him. He was smiling. They were both smiling.
"Remus, you have something on your chin. Just there. Just..." Snape motioned below his lip. "Here, let me." He stood from his chair, his left hand clenched. Anxiously, he raised his arm to Lupin's face and began rubbing at his skin. Remus chuckled at how ridiculous the two of them must have looked. Snape saw the opportunity and, catching Lupin off guard, pushed a chunk of fudge into the man's unexpecting mouth.
"Severus! My teeth are stuck together! I can't... How could you? Just you wait, mister", Lupin barely managed to say between trying to chew and act serious.
The two men were laughing.
It was Christmas time, and they were laughing.