A/N: Prompt from anon, and filled by me because I'm a dork: "Sherlock decides to prostitute himself for research in a case. What he doesn't anticipate is that everything goes wrong - non-con, rape Terrified, injured, abused and desperate he calls John for help. please please, you talented people!"
Sherlock needed to know… he needed to know the circumstances of this murder. Nothing quite seemed right about the circumstances to have prompted something violent—yes, the victim was a prostitute and had the potential of being discovered and causing scandal. But the woman was not high class by any means, and the man she last serviced was single, therefore her clients was neither a wealthy businessman or someone married, and had no cause to kill her. Obviously, because of her poor hygiene and wildly outdated outfit, she had no money which was worth killing to steal. She had no children and the autopsy reported her not pregnant, and it just did not make sense.
There had to be something, though, something he was missing! Maybe it was in the experience of it all, maybe it was only that he did not understand because he hasn't had any experience in the area of prostitution. Maybe he could understand if he tried it.
It did not take deduction to spot a prostitute on the street, and idiot looking for one would know, so all he had to do was change the way he carried himself. A slight tilt of his pelvis to make him seem more open, face pointing down so that he had to look through his lashes at those who walked by. Sherlock preferred to seduce in a slow and harmless way, like with Molly, in order to get his way, but this sort of blatant display of fake-attraction was interesting as well.
Finally, a man approached him who looked willing to trade money in exchange for sexual favors. Sherlock didn't think too heavily about the interaction leading up to his intended experiment, he was too focused on recording the variables in his mind.
Caucasian male, 34-37 years old, previously married (unattached to first and second ex-wife, no children), of a typical means, and only recently started indulging in "professionals"—most likely the general sort of fellow whom might have been with the victim a limitless amount of times.
They together walked a short distance to the hotel room Sherlock had arranged for this encounter. Everything went according to his predetermined timeline when the man suddenly pushed him back onto the bed by a hand on the throat and started undoing his belt buckle with the other arm.
Sherlock was no weak and helpless prey, but before he could deliver a perfectly aimed kick, his assailant punched him furiously in the head, hard enough to blur his vision.
The man was quick and furious in his use of Sherlock's body, making many bruises. As he approached orgasm, his hands restricted even tighter around Sherlock's pale neck and caused the consulting detective to black out.
When he came to, his breaths were quick and ragged. Each inhale hitched roughly and he sobbed on his exhale. Taking a physical account of himself, he noted that every part of his body hurt, but his legs most noticeably cramped with lack of blood while a stream of blood leaked from his nose. In his unprecedented panic, he could only think of calling John. Once this action was completed, he let himself be overcome.
John arrived quicker than Sherlock could have thought possible, but then again, he wasn't thinking very well at the moment. John checked him over, examining his eyes and the capillary refill of his finger and toenails. The good doctor made him stumble around the room to try and stimulate blood flow, and later forced him to lean forward between his legs and soothingly rubbed his back until he could again control his breath.
In the dark hotel room, John seemed nothing but calming and comforting, but when they stepped together into the streetlights (John supporting him, because his legs still ached), his face was fierce with protective anger.
They never talked about what happened that day, though Sherlock found a way to solve the murder case and he knew that John had put together that it was an experiment when he went on his rant about the danger of prostitution. John accompanied him even more often on the most tedious of trips, and eventually Sherlock confronted him.
That night ended much better than his experiment, with kisses and gentle hands.