John snuck up behind Sherlock, who was swearing furiously in what sounded like French under his breath as he worked. He slid his hands around his partner's waist, resting his head gently on Sherlock's shoulder. Usually, John didn't interrupt Sherlock's experiments, but the moment Sherlock broke a language barrier, John knew he needed a distraction.
"Where did you even learn French?" John asked. For a man so painfully meticulous about what he did and did not allow in his brain, another language seemed pretty superfluous.
"Merde," Sherlock muttered, setting down his pipette and turning away from the microscope. "My mother was born and raised in Lyon. She came to London in her twenties, but she always spoke it around the house."
"Your mother taught you to swear in French?" John repeated in shock. Sherlock didn't often reveal details from his past, especially when they involved his family, so really John didn't know if this was out of character or not for the infamous Mummy Holmes.
"No. I figured it out." Sherlock gave a devilish grin. "Mycroft was always trying to get me to stop. Mummy found out when she came into my room during an experiment. I thought she was Mycroft, so I may have shouted a few rude things." He shrugged.
John grinned. "You? Rude? Never," he teased. "But now you've got to teach me some." Sherlock chuckled, turning completely around to face John.
"All right. This is the only one you'll ever need. T'es vraiment trop con," Sherlock said slowly, enunciating clearly so John could pick it up.
"T'es vraiment trop con," John repeated, rolling the words around on his mouth. Sherlock barked out a laugh. "What?" John demanded, and Sherlock chuckled again.
"Your accent is atrocious," Sherlock said.
"You should hear my Farsi," John laughed. "On our days off, I wasn't allowed to speak to the locals for fear of offending them." Sherlock's eyes lit up, and John knew he wasn't going to get out of this without embarrassing himself thoroughly.
The detective locked his hands around John's neck. "I should like to hear it," he cajoled, and John gave in, knowing it was easier than trying to argue with the man when he was set on something.
"Farsi e man bad ast," John muttered. Sherlock grinned, leaning up to press a kiss to John's cheek. The soldier took encouragement from the affection, and continued. "Motavajjeh nemisham," he whispered. "Nazari nadaram. Doset daram."
"And what does that mean?" Sherlock demanded, kissing John's forehead sweetly.
"My Farsi is bad…" John leaned down a kissed Sherlock's temple. "I don't understand…" He kissed Sherlock's cheekbone. "I have no idea…" Another kiss, this one to the corner of Sherlock's mouth. "I love you." A kiss to the lips.
Sherlock gasped into John's mouth, a smile tugging at his lips as he kissed John back.
"Mon français est assez bon. Je comprends toujours. J'ai un idée. Je t'aime," Sherlock whispered. John grinned into Sherlock's neck, not needing a translation for the last phrase, before he pressed a kiss to Sherlock's throat.
"John!" Sherlock shouted a moment later, when John nipped lightly at his collarbone. "It isn't nice to tease."
John pulled back with a smile. "Hmm. Didn't you have an experiment on?"
"Je m'en fous, ça peut attendre." Sherlock spat out, standing up and pushing John against the nearest wall before all but attacking him with his mouth.
Well, it didn't look like anything was on fire or poisonous… John supposed whatever else they had on for the day could wait. After all, John fully intended to hear a few more choice phrases before he was done with Sherlock.