Here's a little nod to a pairing that never gets enough love, but is one of my favourites.
Sherlock drapes himself across one of the prissy, over-stuffed armchairs and fusses irritably with his boutonniere.
"Mycroft, I refuse to believe you're actually going through with this. Greg's going to be devastated, you know."
Mycroft archly raises his brow. "Who, pray tell, is Greg?"
"Detective Inspector Lestrade. He's been harbouring a not-terribly-secret crush on you for quite some time now, ever since you felt the need to rescue me from that particular case with the dru-"
"Sherlock, could we not discuss your drug habits or the ridiculous soap opera that is your life on my wedding day?"
Mycroft, usually so unflappable, actually looks nervous. Sherlock relishes the thought and debates snapping a discreet photo with his phone, but doesn't particularly like the idea of having the entire SIM-card memory remotely wiped once his brother's less distracted.
"Does she love you, My? This isn't some sort of contrived career move on her part, is it?" Even Sherlock is surprised at how concerned his voice is coming out. "I still can't believe you listed her name as Clytemnestra on the invitations. What is her name, anyway? I should hope you actually do know it."
Mycroft sighs theatrically. "Strangely enough, she does love me. Sometimes I still wonder why, but she does."
"Well then, let's go out there to see your blushing bride."