John almost dropped his armful of groceries when he spotted the little brown package sitting innocently on the steps leading to 221-B. It came. He shifted the bags around, reaching down to pick it up. Funny. Its packaging was a lot smaller than he expected. Maybe they folded it a special way. He carefully made his way up to the flat, trying not to drop anything, god forbid the box. If Sherlock saw it before he had the chance to explain…. John shuddered. He still hadn't even thought about how he was going to explain this.

"Maybe just this once, he'll have an open mind. Wait. What am I saying? It's Sherlock."

The door swung open and the bags were snatched from his arms as he fumbled for his keys.

"What took you so long?" Sherlock demanded, whisking John inside.

John shrugged and followed the detective inside to put away the groceries. "There was a long line at the store."

Sherlock ignored him and grabbed his coat. "Lestrade has a case for us. Now."

"Let me just put these away first."

"Hurry." Sherlock's eye fell onto the package sitting on the table. "What's that?"

John straightened up and swung the refrigerator door closed. "Ah, Sherlock, before you jump to conclusions, let me just explain, see-"

"What on earth is a Karmasheetra?"

"How did you-?"

Sherlock picked up the box and pointed to the shipping label.

"Right." John blushed. "Anyway, I ordered it. It's sort of an aid. Aid in bed. I thought it would be fun to try since we're, well, you know, a…"

"A what, John?" Sherlock smiled at him knowingly. John still wasn't completely comfortable with their relationship, and Sherlock knew it. But if this Karmasheetra thing was the thing that would help him, then Sherlock would give it a try.

"…Together as a couple." John finished, embarrassed already. "We could, ah, use it tonight maybe? After the case?"

"Forget the case. Let's try it now."

John blinked in surprise. "But Lestrade-"

"Lestrade can wait."

"Who are you and what have you done with Sherlock Holmes?"

Sherlock smiled and handed the package to John. "Just this once."

"How does this even work?" John asked, eyeing the bright sheet with trepidation.

"You bought it." Sherlock retorted.

"Right then." John puffed his chest out, drawing up the courage to continue with the whole idea. "I'll be blue and you be pink."

"Pink? Why blue and pink? Are they trying to insinuate something?" Sherlock asked suspiciously.

"We'll take turns." John reassured and crawled onto the bed. "As soon as we figure out how to do this."

"Sherlock, your foot is in my face."

"Well then move your head. Where's the other space for my hand?"

"OUCH! Not there! That's my spot!"

"No it's not, there's a three on it. It's mine!"

"It's blue! Yours is pink, remember?"

"Well maybe I want to be blue now."

"God fine, just move your leg so I can change my place."

"John, my other hand is stuck."

"Ugh."

"I think this is right." John managed after shifting into a strange position. Sherlock moved over top of him, resting his chin on John's shoulder.

"Finally." he murmured and rolled his hips forward, making John inhale sharply and bite his lip to keep from making a sound as Sherlock thrust inside him.

"Shit, Sherlock. I wasn't-"

"If I waited for you to be ready John, I'd be waiting the entire night." Sherlock replied, smoothly working in and out of John's arse.

John gave into his need for release. With a breathy, uncharacteristic moan, he came, staining the pink and blue spots on the sheeting. "Now look what you did."

Sherlock only hummed his approval and continued to fuck him. "The pink and blue was too jarring anyway." he assured.

"I fucking hate you."

"Mmm-hmm."

It was a long night to say the least.

John wasn't sure, but he thought Sherlock said 'sorry' more times that night than he did in his entire life. When they finally figured out how to work all the new positions and colored spots, they alternated between being the dominant and the submissive, though Sherlock seemed a little too enthusiastic whenever he found himself in a dominant position. He had quite a talent for finding areas of John that made him melt in sheer bliss every time he touched him. John enjoyed denying Sherlock's pleas for mercy, silently gloating to Irene in his mind as he did so.

"That was… satisfying." Sherlock said, cradling John's head in the crook of his arm. He settled back, pushing the stained Karmasheetra off the bed with his foot, taking care not to jostle John's half-asleep form.

"We should try sex aids more often." John agreed, sleepily.

"Yes. We really should."

"This really was a good idea after all." Was John's last thought before he slipped into a dream-filled slumber.