The call came on an ordinary Thursday evening. If it was anyone else, Sherlock wouldn't have answered.
"John."
"Er, yes. Hello."
"You wouldn't have called if it was something you could say by text."
"Yes, well-"
"Out with it," Sherlock said more forcefully, "I'm terribly busy." He wasn't, his latest case had finished yesterday.
"It's Mary."
Of corse it was.
"There's something I'd like to give her," John explained. "It's very specific and you're the only one I'd trust enough to even consider-"
"I accept," said Sherlock.
"I haven't-" A pause. "You would?"
Sherlock sighed. "To save you the trouble of saying it aloud, I would indeed consent to a threeway with you an your wife."
"How- never mind." Somewhere under John's embarrassment was the hint of a laugh. "This Saturday at nine?"
"If I'm not on a case."
"Fair enough," John said.
They disconnected.
---
There was a new case before the set time, but it was open and shut in less than twenty-four hours. Hardly worth mentioning. The enormous effort Sherlock put into solving it quickly so as to keep his appointment with the Watsons was also of little importance.
Mary took his coat a the door. "Good to see you, Sherlock," she greeted him. Her smile wasn't strained or empty. She was legitimately glad that he was here.
"Mary," he nodded in return. A quick glance over her person told him what would have taken the average person minutes of nervous dancing around the subject to discover. "This isn't a surprise. John told you ahead of time."
Another grin, this one a little cheeky. "That's right."
---
There seemed to be some sort of malfunction in the part of John's brain that was responsible for maintaining eye contact. Everything else was in place, his hand was steady when he handed Sherlock his tea, but he was utterly unable to look at his former flatmate.
Sherlock set the mug in front of him, untouched. Mary sat next to him while John made an excuse to visit the kitchen again. Sherlock watched him leave, weighing the possibility of him backing out of his own offer.
"He'll come around," Mary said.
"Hm," Sherlock mumbled as a response, attention fixed on the kitchen entrance. There was a moment of comfortable silence as Mary finished her tea, followed by a clink when she set her empty cup next the Sherlock's full one on the coffee table.
"Do you mind if I start?" Mary asked.
Sherlock dragged his eyes away from the kitchen and turned toward her. "I see no reason not to."
A slight smile. "Alright."
She straightened up and kissed his cheek. It was light, meant to break the tension. Sherlock could see why John liked her so much. She was as considerate as John was loyal.
Sherlock cupped her face for a real kiss. It was minimal, a simple slide of lips. After a few seconds they separated. Mary got up from the couch and held out a hand for Sherlock to do the same. She didn't let go as she led him to the kitchen. John was fumbling with a coffee maker. It didn't take much to deduce that his guilty look stemmed from the image of the sitting room reflected on the glass of the china cabinet.
