In Your Face Mycroft!

Prompt by ImpishTubist on tumblr: "I need fic where Mycroft tries to charm Lestrade in his smarmy way and Lestrade is having none of his bullshit but that doesn't deter Mycroft. And later on Lestrade's finally had enough and he's like, "You know I'm bleeping your brother, right?" and then just walks away with this smug grin on his face. And Sherlock's never been more turned on"