Sherlock, as evidenced in The Blind Banker, is an expert cockblocker.
Intercepted
"So, we couldn't actually treat him because of the language barrier. You think we'd have one student in our class that spoke at least a little French, but luck was not on our side that day," said John, chuckling as he recounted another story to Mary.
She grinned and said, "Tell me another! I'm liking Bart's already." She subtly reached out a hand to his wrist suddenly the doors to the library swung open and Sherlock strutted in.
"Come, John, I've got something to show you. Oh, hello, Marian. Hope I didn't interrupt anything," said Sherlock, smiling.
Prompt was from The90'sKid and it was: language barrier