She was so close that Severus had to really fight the urge to just lean in and kiss Lily. It would, of course, not be proper, especially not in such a public place. For a moment he moved closer but stopped himself just in time. He was not going to make it more difficult for her. He loved her too much to make an upsetting evening even more upsetting by kissing her.
When the music started again it was to fast for the only dance Lily had taught Severus. He didn't move for a moment before he tried to dance with Lily anyway. What ever happened he would try to get better at dancing.