Happy Easter, John. (A prompt; may add to this later depending on how my chem homework goes)
Sherlock notices the subscript on the calendar. “Easter,” he thought to himself, a wicked smile tugging at the corners of his lips. “Chocolate is associated with the holiday, isn’t it?”

The detective eagerly trotted off to the store, which was still (surprisingly) open, despite the religious holiday. He gracefully went to the frozen novelties aisle and grabbed a bottle of chocolate sauce. “This should do it,” he thought to himself as he walked up to the cash register and (flawlessly, unlike John who was notorious for having a row with the machine) paid for his syrupy treat.

Upon the detective’s return, John was pacing about the living room, dressed in his Sunday best. “Sherlock, there you are,” said John in a hurried tone. “Come, we best get going to mass…”

Sherlock said nothing, but instead pulled the chocolate syrup out of the bag. He looked at John with that familiar gleam in his eye.

“Christ, Sherlock! Not now,” John protested, pulling at the hem of his vest to straighten it. “We’ve got to go to Mass! It’s the proper thing to do! Mycroft and your mother are meeting us there!”

Sherlock whipped his phone out of his trouser pocket and sent a text over to his brother:

[Can’t come. Bad accident. Involves chocolate. -SH]

“It’s taken care of,” the detective said, returning his phone to his pocket. “There’s been a bad accident involving chocolate,” he said, taking catlike strides over to John.