At first, Lestrade thinks he’s imagining it; he only caught a quick glance, and it really could have been anything. But, no, another minute of watching reveals what he’s looking for. As John moves his arm to point at something in the crime scene, the collar of his jumper shifts just enough to reveal a hickey on his neck. Lestrade smirks. He supposes it’s rather juvenile of him to be snickering over a hickey -they’re both grown men, it’s no big deal. No, the reason that this is making Lestrade so giggly is because only half an hour ago he noticed a similar distinctive red mark gracing Sherlock’s pale neck as well.
He also can’t help but notice how the two were acting around each other. When John caught sight of the mark on Sherlock’s neck, he ducked his head with a small smile, an almost unnoticeable blush spreading on his face.
On the other hand, when Sherlock glanced over at Lestrade from where he was standing next to John and followed Lestrade’s gaze, he smirked, his teeth showing in a possessive grin that clearly said, “look, he’s mine. I marked him. Mine.” John turned, catching the end of this silent confrontation, a bewildered look crossing his face before he continues his explanation.
Sherlock looks ridiculously smug, the bastard.
Lestrade is just waiting for the rest of the boys at the Yard to catch wind of this; they’ve had a betting pool going on how long it would take the Consulting Detective and his Doctor to finally get together since almost the first week after John arrived. The two stubborn men have, as far as he knows, remained ignorant for far longer than everyone expected. Quite a lot of people will be losing money (Anderson, surprisingly, will not be one of them -Sherlock would be livid if he finds out he’s benefitted Anderson in some way).
Lestrade is happy for them, though; any idiot with eyes can see they’re good for each other. He knows better than most -he’s known Sherlock the longest and has seen how his behavior changed for the better when he met John. It’s sweet, in a slightly twisted way, how they glance at each other across the crime scene, their eyes softening when they meet each other’s gaze and a small, almost shy smile appearing before they return to what they were doing.
Over the length of the week, he notices a new mark on John almost every day (either John is doing a bad job at hiding them, or he isn’t trying very hard to). I suppose I can’t really say I’m surprised, though, he thinks as he absently rubs the marks on his collarbone. He knows from personal experience that the Holmes tend to be very enthusiastic about marking what is theirs.