London is hot. It's high summer and for a few torturous days the temperature reaches into the mid-30's.

Sherlock is tetchy and John is grumpy and even Mrs. Hudson has lost her usual joie de vivre.

There seems to be nowhere in the flat to be comfortable. Sherlock's room is dark but only has one small window that opens onto the alley and gets no airflow.

The main room has two windows but one either leaves the heavy curtains open letting in too much light, or draws them blocking out much of the air. They've covered the couch in a sheet after peeling hot, sticky skin off of the leather one too many times.

John's room has two windows and lighter weight curtains, but it's on the top floor so the heat is worse, trapped near the attic. Still, it's (theoretically) his and he retreats there after one more sniping match with Sherlock.

He must have dozed, because when he wakes up, the light has shifted and Sherlock is standing in the doorway with something in his hand.

"I brought you some chocolate." It's the closest that Sherlock will come to an apology and John knows it. He holds out his hand, but instead Sherlock smiles his I'm-even-more-clever-than-you-think smile and joins him on the bed.

John stripped from the heat and Sherlock's shirtless. Much as he'd like to be angry, John can't remain indifferent to Sherlock's bare skin or his smile, or his anything, actually.

Sherlock unwraps the truffle and nibbles a little bit, cracking the shell.

"I thought it was for me!"

"Oh, it is," Sherlock grins. He pushes his finger inside the truffle. The ganache is viscous in the heat. He runs a chocolate-coated finger along John's cock, John's cock that's definitely showing an interest now. Heated by their skin the chocolate becomes completely liquid as Sherlock smears more around the shaft and up over the head. It dribbles down onto John's stomach and into his pubic hair, but he's beyond caring now because it turns out that melted dark chocolate ganache has the perfect consistency for lubrication. Yeah, really perfect. That perfect.

The truffle in Sherlock's left hand is disintegrating rapidly and he's able to pour what's left of the filling directly onto John's cock. He holds out the crumpled bit of the shell to John and John sticks out his tongue to catch it. Sherlock lets his messy fingers linger, lets John start to clean them up as he strokes John's cock with his equally chocolate covered right hand. He clasps John's shaft in the tight ring of his fist and slides up and down, up and down slowly, the chocolate surging between his fingers.

John sucks Sherlock's forefinger into his mouth. The rich taste blends with the salt of Sherlock's skin like sea salt in a gourmet chocolate bar Harry once gave him. Sherlock's fingers are smearing chocolate over John's face, so John catches Sherlock's hand and sucks the three middle fingers into his mouth and just draws on them, hollowing his cheeks. Sherlock moans.

"You have chocolate around your mouth," says Sherlock.

"Mmmm…" John replies. He lets Sherlock's fingers slip free and runs his tongue around his lips slowly. Sherlock moans again and shuts his eyes.

Sherlock lowers his head to start sucking on John's chocolate covered cock while John continues to clean his other hand, licking the palm, up the thumb, in between the fingers.

As Sherlock sucks, he's pressing chocolate fingerprints across John's abdomen and thighs. All that John can smell is chocolate and his and Sherlock's sweat in the hot room.

Sherlock lets John's cock slide from his mouth and looks up, so John dips his finger in the chocolate that's pooling on his stomach and traces Sherlock's lips with it. Sherlock's whole mouth is ringed with chocolate, like a child who's shoved cake into his mouth. It shouldn't be as erotic as it is.

"Fuck," John murmurs. "This gives new meaning to death by chocolate."

Sherlock returns to sucking John's cock, faster now that the chocolate is almost gone. John pushes his fingers through Sherlock's hair, probably rubbing chocolate into it. They both need showers by this point so a little more of a mess is hardly going to make a difference. He's getting close and Sherlock knows it. They're both moaning and Sherlock's head is moving faster until John cries out and comes.

Sherlock lets John's cock slip from his mouth, gives one last firm stroke and catches the last drop of come with his tongue.

"Interesting," he says.

"Interesting?"

"The taste was…not unpleasant. Salty and sugary, just a bit of that acridness that catches on your teeth."

"Perhaps we should market a new flavor of candy bar."

"Come flavored?"

"We could really say that it melts in your mouth."

"Releases its creamy goodness?"

"Explodes with sensation. What brought that on?"

"Did you know that the ideal melting point of chocolate is 36 degrees? It's engineered to melt at body temperature."

"Ah, so this was an experiment?"

"No, well, yes, I suppose."

"You know that I'm not going to be able to eat chocolate or even smell it again without getting hard?"

"Hmmm…that seems a small price to pay for science."

"Shut up and come up here and kiss me with your chocolaty mouth."