Yet another crime scene. This one was a brutal murder—a male in his late teens was lying in an alley, his head crushed and all of his major limbs containing at least one broken bone. John was doing what he normally did: that is, minimizing contact between Sherlock and anyone whom he might offend. He was talking to Lestrade, trying to understand the process of legal evidence taking (he sadly knew enough about the other type to become a virtual expert) when he heard it:
"I might be stupid, freak, but at least I can handle a relationship! Look at you; I bet even your mother preferred that suit-wearing ponce over the psychopath that she gave birth to!"
John turned in a rage, preparing to shoot Anderson himself. He was fast enough to catch a glimpse of genuine pain in Sherlock's eyes, before the mask of the Great Detective snapped firmly into place. "Firstly," Sherlock replied in a lazy tone, like a cat stretching in the sun, "my brother is many things, but he is not a ponce. He doesn't need to fake intelligence and class; he has it in abundance. Maybe that's why you have so little." He ignored Anderson's enraged spluttering and continued. "Secondly, I am perfectly capable of handling a relationship and have done so multiple times in the past. And I must say, I appear to hold them down better than you. At least I have the good grace to break up with my partner before cheating on them with the garage attendant on… Warwick Street, I believe." Sherlock took a moment to appreciate the shade of white Anderson turned, and then reported to Lestrade. "The killer is a male stripper at the Inferno night club, killed him with a rubber prop from his act—likely a truncheon from a police stripper. Check under the killers nails for traces of the victim's moisturizer—it's an exclusive brand." And with that, Sherlock motioned for John to follow him, and stalked away from the crime scene.
"I don't understand it," John said later, as they rested in their apartment. Sherlock looked up from his newspaper briefly, brow furrowed. "I would have thought it was obvious. You see…" John cut him off. "I know about the case—I saw the stamp on his hand and the traces of silicone in the wound." Sherlock looked back at his paper, but not before John saw the flash of pride in his eyes. "So then," Sherlock continued, "what is it that has you perplexed?" John tapped his knee until Sherlock looked at him, and then replied. "I don't understand how you can go on, day after day, with those people hurting you. You do get hurt from the comments they sling, so how do you put up with it?" Sherlock folded the newspaper, and then turned to face John.
"When people say they wish they were an animal," he began, "they often say that they wish they were an eagle, or a wolf, or a bear… but if I could pick an animal, I would choose the duck. Ducks have an uropygial gland, or a preening gland under their tails. It releases uropygiol, which is oil that waterproofs the duck's feathers. Without the oil, the bird's feathers would become laden with water, and they would sink. But ducks, they've evolved a way around it. That's why I want to be a duck. I have had abuse thrown at me since childhood, but I've developed a way around it. I just delete those who hurt me from my mind, and the insults just… slide right off. It's not perfect—sometimes the insults stick and sometimes it hurts. But I still try to improve the process, because that way I can protect myself, and everything will just slide off." John nodded, and they return to their activities. But if Sherlock seems to want contact more than usual, John doesn't mind. And when Sherlock finds a wooden carving of a duck right next to his skull, he takes to carrying it around with the defence of "people stare at me when I talk to the skull, don't they? Now hurry up John, there's been a stabbing in Westminster, and I want to get there before Anderson messes up the evidence too badly…"