Severus knew how people danced of course, but still it surprised him when he was holding Lily so close, for a moment he didn't know what to do with his second hand. Noticing that Lily did not seem to have any trouble holding on to him he gently placed his hand on her back, not too low to be inappropriate.
At first he tried to follow her lead without looking down but that was not as easy as it sounded, before he knew it he was staring down at their feet wondering why something like dance seemed so much harder then the most intricate potion.
"Not too bad..." He muttered, not really convinced about that yet though. He was sure he looked like a dancing wooden chair.