Anger. Not the morphine then, nothing like it. Cocaine, much more likely, much more usual. He shakes his head in pity, and then gets knocked to the ground. Even if one was to be expecting it, having a one-ninety pound long, lanky figure throw themselves at you is enough to knock one off his feet, and Mycroft is no different, falling with a huff and a clamoring to gain purchase against the floor.

He's not the fighter of the two of them, so he mostly blocks blows with his arms over his head, letting those fists rain down over him, and there's one punch that connects to his jaw with a crack. It's sore, it hurts, and he writhes to try to get free.

Unexpected results. Or not so unexpected one might say. He doesn't enjoy being pinned any longer, fighting relentlessly to shove his brother off before evidence of any betrayal of the bodily kind becomes apparent. He's not a teenager, hardly one to explain away the natural order of things, because having someone sitting on you and beating you with their fists isn't supposed to make you aroused. At least, not in such a setting with his darling baby brother.

So it shouldn't to him, and he twists his body to the side, snarling back in kind with Sherlock on top of him and attempting to shove him away. More vigorously now, jerking up and trying to hit him, punch him, throw him down, do whatever he possibly can to get him away enough to the point where he can throw him off of him and get him to stop writhing the way that he is. "Don't tell me your life is your own - " he hisses, snarls, and manages to connect his gaze with him, clenching his jaw. "You don't even know how to keep yourself alive."