Written for megan_moonlight who wanted protective Lestrade. While it's not conventional protection, I think it fits.
"Stay."
Such a simple word, but it held so much meaning. Lestrade's hands froze from their position on the button of his half fastened shirt, turning to look at Mycroft lounging slack and sated against the rumpled white sheets. Lestrade couldn't help but appreciate the image; the long limbs sparsely dusted with light hair, the slight outward curve of his belly, his thinning hair mussed from its normal perfection by Lestrade's own fingers, while not conventionally handsome, never managed to fail to take his breath away.
Lestrade wanted nothing more than to crawl back in bed with him, but it was late, so instead he replied. "I've got to be at the office early."
The corner of Mycroft's mouth rose in amusement, his eyes alight with wicked mischief. "Just sleep. We're closer to the Yard then your flat, and you're already here. Why waste a perfectly good bed?"
Lestrade was puzzled by the request, his gut tight and unsure. In the three years that they'd been meeting like this, they'd never spent the night, never took it beyond the physical. That had been the original deal, but this was different, was more, not something that they'd planned on. Understanding Mycroft, Lestrade knew that he always had a plan, but despite searching his face Lestrade couldn't read a thing.
Maybe this was just Mycroft being logical.
As if, a part of him mused in mockery, but Lestrade had made his decision and stripped off his shirt again before kicking off his trousers and climbing back into the bed. A very comfortable bed.
Reaching over, Mycroft shut off the light, blanketing the room in darkness. After long minutes of lying stiff and still next to each other, Lestrade thought, screw it, and twisted around, tugging Mycroft into position against him.
"Oof," Mycroft gasped. "What do you think—" He broke off as Lestrade finally settled them, his chest against Mycroft's back, and one arm draped across his waist.
Lestrade smiled in the darkness and placed a soft kiss against Mycroft's neck, delighting at the shiver, at the intimacy of the position. It took a minute for Mycroft to loosen up in his embrace and Lestrade couldn't even imagine what was going through his mind, what he was making out of all of this. Maybe he'd planned this after all. Finally relaxed, Mycroft tangled his fingers loosely with Lestrade's and shortly after, his breath evened out with sleep.
It should have been odd, this—them in bed together for a reason other than sex after their usual meeting about Sherlock. It wasn't the most normal relationship, but they both enjoyed it. Took what they needed with no strings attached, no expectations. But lately, or if Lestrade was truthful, for awhile now, he'd been looking forward to these meetings far more than he should have, always feeling more disappointment than he cared to admit when something came up and one of them had to cancel.
However, now in the darkness of the room, curled around Mycroft as he was, there was no denying that somewhere along the way Lestrade had lost his heart to this man. For all the British government Sherlock claimed his brother to be, Lestrade knew that Mycroft was a man just as any other, a brilliant man, an often infuriatingly smug man, a frightfully powerful man, but still a man.
Doing what he did, Mycroft sacrificed many things in his life as the dangers were too great for all involved. Lestrade could not profess to know what Mycroft felt, but this couldn't be brushed off as mere logic as they'd been in this same situation many times before, and yet this was the first time Mycroft had asked him to stay. This changed things, Lestrade knew, but he could keep his silence on this. It was the least he could offer.