The door to John's room burst open and Sherlock came barrelling through.
"John, I need - "
Few things could stop Sherlock from finishing a sentence. John had lost count of the number of times Sherlock had indifferently walked in on him in various states of undress, or even in the loo. Protests of indecency were scoffed at or flat-out ignored.
Now, though, Sherlock froze. His eyes darted about the room, taking in the scene before him. John had his girlfriend, Anna, pinned down on his bed; his knee was wedged between her thighs, one hand was holding her arms above her head, and the other hand was covering her mouth. She had turned her head toward the door at Sherlock's sudden intrusion and her eyes stared up at him, wide and shocked, as she squirmed against John's rough hold.
It took less than a second for Sherlock to start moving again. Two long strides carried him from the doorway to the bedside.
"Sher-"
Whatever protest John had been about to make was cut off as Sherlock grabbed two fistfuls of John's jumper and shoved with all his strength, knocking him completely off the bed. John gave an audible "Oof" as he stumbled back toward the door, barely managing to stay on his feet. Sherlock slid an arm beneath Anna's shoulders and lifted the dazed woman to a sitting position.
"It's all right now," he muttered to her, keeping his eyes trained on John. "You're ok."
"What in bloody hell, Sherlock!" yelled John, recovering his balance and throwing his hands in the air.
"I expected better from you, John," Sherlock stated reproachfully. He stood up, blocking John from returning to the bed. Anna's eyes darted back and forth between them.
"'Expected better'? What do you care if I'm finally shagging my girl? I'm not a monk, you know! We've been dating for nearly three months and this is the first-"
Sherlock interrupted again, this time with steel in his voice. "No matter how long it's been, she doesn't owe you anything. Spending a certain amount of time with a woman does not equal permission for you to take what she doesn't want to give you."
John's jaw dropped as he realized what Sherlock was saying. "What she doesn't... Sherlock, you've got this all wrong!"
"Oh, I supposed she asked you to force yourself on her?" Sherlock bit out.
"This was a mutual decision! I realize it may have looked a little, erm, strong...but I swear to you, she wanted that! It wasn't even my idea!"
"Don't be absurd, John," Sherlock started to retort, but Anna's blush caught his eye. "You really asked him to do that?" Sherlock asked her in an unbelieving tone.
Anna blushed even harder. "It's…a fetish of mine. Sorry for upsetting you." She glanced timidly up at Sherlock. "It's very sweet of you to save me."
"Save you?" John was suddenly uncertain.
"Well, he thought he was saving me, at least. It's the thought that counts, right?"
John sighed and leaned against the wall. All the fight had gone out of him. "I suppose."
"Hm." Sherlock looked back and forth; John had his hands stuffed in his pockets and Anna was nervously tracing her fingers along the edge of the mattress. "That's my mistake, then."
John straightened up. "Yes, Sherlock, yes it bloody well is."
"I suppose I ruined the moment for you?"
John sputtered for a moment before practically growling, "The mood's quite gone now, thank you."
"Ah. Well then." Sherlock gave John his most winning smile. "John, I need you to get me a cheap plastic vase, 13 peonies, and a fresh kidney. A man's life depends upon it!"
