John didn't usually get mail. The mail was always sent to Sherlock, because, Sherlock liked everything to be in his name. This was because Sherlock was still counting down to the day John's going to leave him, even thought John assures Sherlock a million times a month that he's never leaving.
But today John got mail. There was no return address, there was nothing on it but John's name.
John was ripping it open as he climbed the stairs to his and Sherlock's flat.
"Hello, darling, how was your day?" Sherlock called to him from the sofa.
"It-fine-huh-" John was busy reading the card that was inside the envelope.
"John, what's that? Did you get mail? You never get mail." Sherlock got off the couch and met John in the middle of the living room, "Does that make you sad?"
"Huh, what?"
"That you don't get mail."
"No, why would it?"
"I don't know. People like mail. What is that?"
"It's an invitation."
"To what?"
John looked at Sherlock, almost scared, "Holmes Family Christmas."
Sherlock's face went straight. "From who?"
"Marie Thomas. Who is that?"
"My mother."
"Oh. Should I…do you not want me to go?"
"No, no! Do as you please. I'm not going to stop you."
"All right, I'll go then."
Sherlock huffed and threw himself back onto the couch.
"I won't go, then?" John asked, confused.
"No, no. You can come. It's about time you meet my mother."
John smiled and kissed Sherlock's forehead.
Two weeks later, Sherlock and John were packing for their three day weekend at Sherlock's mother's house. John made Sherlock pack a tie, even though Sherlock hates ties, and John made him unpack his special 'When-I-Wear-These-John-WILL-Have-Sex-With-Me' underwear.
"These are my favorite pair." Sherlock said, pulling them out of his suitcase.
"I know, they're mine, too. Which is why you're not going to wear them while we're staying at your mother's house."
"Why not?"
"I'm not going to have sex with you while we're at your mother's house."
"Why not?"
"Really, Sherlock?"
"I've had sex in my mother's house before."
John shook his head, "For the sake of not wanting to get into this now, I'm not going to ask. You're not wearing those this weekend. It's three days, you'll be fine."
Sherlock sighed and put the special underwear back into his drawer.
The weekend started early the next morning. A car from Mycroft arrived at 5 AM and drove them three hours to Sherlock's mother's house. They were to be there on time for breakfast, and when John asked why they didn't just go the night before, Sherlock got quiet.
"I just don't want to be up there for more time than I have to be."
"You don't like going to your mother's?"
"Not particularly. I like to see my mother. Everyone else is just in the way."
"Everyone else?"
"We have large Christmas parties every year."
"Why?"
"I have a large family."
"How large?"
Sherlock thought, John could tell he was counting. "My mother has six sisters, no brothers. But they're all married, so I've got six aunts and six uncles. And each of them have at least two children, so that's over twelve cousins. Plus, all of them have families, so that's-"
"I get the picture, Sherlock."
"There's just a lot to the Thomas family."
"Why is your mother's last name Thomas, anyway?"
"Well, you see, her and my father were never actually married. I guess they just never got around to it, probably both fearing that the other would leave one day. And one did, so, I guess they were right."
"But, then why is your last name Holmes?"
"It was my father's last name."
"I see."
"Actually, technically, my last name is Thomas Holmes. I don't have a middle name, it's just Thomas."
"I always thought that was your actual middle name."
"Nope."
John nodded. He literally learned something new about Sherlock every day.