It always ended with hot chocolate. After every adventure, every day and every time they ran for their lives they ended up with hot chocolate. It was a tradition they had started back when she first joined. Back when The Doctor had worn leather and grumbled about stupid apes, before he and Rose were even that close. They would each make a cup of hot chocolate and sit before the fire in the library, completely separate but at the same time together. Neither of them mentioned how Rose preferred tea and he preferred coffee. This tradition continued even when he changed.
The tradition changed at the same time the doctor did, instead of each making their individual cups he started to make two and bring it to Rose. It wasn't long until a new tradition developed, one that involved swapping drink making duty and cuddling up on the sofa to watch the fire roar. It was incredibly domestic The Doctor would complain with a smile on his face most night. Rose would just roll her eyes and smirk into her mug.
It was Rose who noticed it first. On one of the many nights they sat together in the library she shifted her eyes around and analysed the room for the first time in months. Her eyes widened and The Doctor, so in synch with her, picked up on this immediately. "Rose? What's wrong" he asked shifting himself to be able to look into her eyes. "Isn't it odd how we can miss things so obvious that are right in our faces?" she asked mysteriously. The Doctor felt himself begin to panic. She couldn't know how he felt could she? "What do you mean?" he stuttered out only to get an odd glance over Rose's shoulder at him. "There are stockings above the fireplace." She explained. And she was right. Somehow to TARDIS had decided to add stockings right above the fireplace they sat by each night and neither noticed.
So the TARDIS continued with this. Each night they would come in to see another decoration added. Tinsel above the mirror, paperchains on the ceiling. The Doctor and Rose however were masters at ignoring the obvious so they both silently agreed to just pretend it was completely normal behaviour. Who cared that Christmas was a few months ago? However, it was the mistletoe in the corner that finally caused them to talk.
It was just another night sitting in front of the fire when Rose spotted it. "Doctor? Is that mistletoe?" she asked looking up at the plant on the ceiling. He looked up at the mistletoe and with startling realisation gulped. He looked back at Rose who was sitting next to him looking up at the mistletoe as well. "Well I guess it's tradition." He whispered before leaning forward towards Rose. "Yeah tradition" she agreed leaning forward as well. Their lips met in a burst of fireworks and their hot chocolates, well they went cold that night.