i think he might be fed up with Mycroft's tone and meddling. Also he might not want Mycroft finding Janine in his bedroom therefore he attacks him in order to get him out the door as quickly as possible.

I think it is because Mycroft is so condescending when he says it.

tonnaree wrote:

I don't think it's the phrase itself.  Mycroft and Sherlock have both used it before.  But Mycroft's attitude.

It wasn't exactly "brother mine" before but


...and I think they both would use this phrase ironically.  Mycroft, in this case, could be equally appalled because Sherlock uses him and his authority to get into Baskerville. I'd say: Familiar interaction between the brothers. Nothing unusual.

He actually did use it before; in the scene where Sherlock is getting his shave in TEH it's used!

I think I'm going to have to agree that Sherlock had had enough for one morning. I also think he used the "high" as an excuse. 'Cos, that didn't look like somebody on heroin to me-- and that's what he tested positive for; he acted more like he was on coke or speed. (I play music, and have had to deal with a lot of druggies in my time, so I know what it looks like)