Prompt was the first birthday gift.
"Severus?"
"Hmm?"
It was early January. Severus's birthday was fast approaching, and Harry had no idea what to get him. He decided to ask late at night, when Severus was just about to drift off. He had a theory that Severus might be more likely to answer personal questions when he was half-asleep.
"What would you like for your birthday?"
Severus chuckled sleepily. "I leave that up to you, love." He patted Harry's side. "Go wild."
Harry poked his lover in the side. "Not helpful in the least, Sev."
"Mm, I know."
Well, Harry thought, so much for that theory.