For IAmFire, who wanted to see a bulldog, and Jenna Yemowa who wanted more animals :)
"It's for a case, John." Sherlock's voice carried up the stairs. What John didn't recognise, though, was the strange scrabbling clicking noise, and the panting. Good lord, what'd he done this time?
John barely had time to sit down and brace himself before he was bowled over by thirty pounds of stubby legs, wrinkle, and slobber. The dog crawled onto his chest, happily licking every square inch of his face.
Shaking his head and spluttering, John glared at Sherlock.
"A case, like I said."
"I hope you're not planning on experimenting on him!"
"Nothing so vulgar, don't worry. I need to investigate a professional groomer, several purebred dogs and cats have mysteriously vanished while in her care, I'm assuming she's selling them on the black market."
"You can't just buy a dog for a disguise, Sherlock!"
"I borrowed him."
John tried to look upset, but it proved impossible while the dog was snuffling intently at his armpit. He giggled, despite himself.
"Alright, fine."
Over the next few weeks, Sherlock remembered the dog when it was convenient for him, but neglected to feed or walk the poor thing. John took over dog duty, and soon he found himself rather attached. He kept having to remind himself that this was temporary, that soon he would have to say goodbye to the little bulldog.