Severus had to smile at Lily's playful twirl, he also had to stop himself from tumbling because watching her meant not watching what his feet were doing.
He didn't want to think or talk about the difference between muggles and wizards, the whole pureblood, half-blood and muggleborn discussion was something that filled him with dread. He was half-blood in a house filled with people thinking pureblood was superior and his best friend and the prettiest girl he knew was muggleborn. He just knew that was not going to end well
Severus decided to go with Lily's last statement, pushing the pureblood/muggleborn discussion away for now. "Maybe they will have one with Christmas." He tried, it sounded like the best time of the year to have a ball.