That's an absolutely excellent idea! It makes me wonder what the addictive possibilities are for vicarious heroin use - there won't be any of the physical effects from the actual drug, but would his brain get hooked on the pattern of it? Just experiencing it would surely give him some kind of chemical response. So fascinating :). I don't believe I've ever seen this concept before.
Gorgeously done, too. Love the details all through the story, and Severus' ongoing association with Lucius. In terms of the relationship focus, this seemed more like a Severus-and-Lucius story or a Severus piece, but that last paragraph brings it back to Snarry :).