"Sherlock? Sherlock Holmes, is that you?"
Sherlock spins around, scanning for the source of the voice. There, across the room. John sees who he's focused on. The man is tall and slim, with cheekbones nearly as sharp as Sherlock's, and loose fair curls. Standing between the two of them, John feels distinctly short, stout, and plain.
"Victor! Victor, this is John Watson. John, this is Victor Trevor. He was my friend in uni."
John freezes, anticipating some sort of contradiction, but Victor just smiles widely.
"Sherlock helped me out with some family matters and stayed at our house one summer."
The surprise must be clear on John's face, and Sherlock lets out a sharp laugh.
"Yes, John, someone was able to put up with me before you came along."
"Sherlock's looking healthy, clearly you're good for him. It was nice meeting you, but I've got to run." Smiling warmly, Victor shakes both their hands and runs off.
"He was nice." Whatever insecurity John may have felt is gone.
"He was. Seems like he still is. I'm glad he didn't have his awful dog with him."
"Sherlock, it's been nearly ten years since you've seen him. The dog is probably..." John looks for a tactful way of phrasing it.
"Dead?" Sherlock clearly has no such compunction. "Good, that thing was a brute."