A 221B story. (221 words with the last word starting with b)
Along came a spider.
Having a friend like Sherlock is an adventure. I know you typically think of the rooftop chases across London, kidnapping attempts, attacks and even possibly the questionable contents of the kitchen. Having a friend though who hates spiders can be quite an adventure on its own. Say for example you're both sitting comfortably in the living room. You're sitting at the desk, your laptop placed in front of you as you go about typing away happily and your friend is across the room lying indolently upon the couch. They say something, though you've missed the exact words, and you look up and turn toward them. Something is on the wall above the couch and it catches your attention. You keep yourself focused on it wondering when it ended up there. They will look at you quizzically for your lack of response and turn to look at the wall. Laugh hysterically when they only need one jump to clear the room and plaster themself to the opposite wall. Get up and grab a flyswatter for the (actually quite large this time) spider. Make sure you don't miss that first shot, getting to watch the panicked, headless chicken routine when it starts scuttling away (in what must be your friend's direction) isn't worth the scream that'll be leaving you with your eardrums burst.
The scene has been altered but based on real events. Poor Jay Feathers but she did suggest a humor story if I was going to write a Sherlock piece.