The beauty to me of the song is how, like the album as a whole and the one after it, Exile on Main St, take something considered socially "vile" and turn it into something sexy. There's no surprise that Keith Richards, here at the height of writing his best songs, I think, was also in the middle of his heroin addiction.
Of course, it's wrong to glamorize drug use and all that D.A.R.E. crap, but the songs do the work in "Dead Flowers," even though the song is ostensibly against the use of the drug. Don't you just feel aroused when Mick looks at you when he sings it!
He does it with the next line too, nearly avoiding eye contact, but just barely making it. It's incredible and creates the headspace of the whole song in those moments of the video above (you can watch the whole thing here).
Johannes' post focuses on the first line of the song, discussing the "upholstered chair." I think it would be great to think of the parallel of "upholstered" to "rose pink," both signs of indulgence, certainly.
The indulgence of the song is purposely contrasted to sort of dirty degeneration of the second set of lines in each verse:
Well I hope you won't see me in my ragged company
You know I could never be alone
I'll be in my basement room with a needle and a spoon
And another girl to take my pain away
Both couplets make me think of drug use: the company one keeps of other users, certainly. Smokers who quit say that one of the things they miss is the people they meet.
How can a line about taking heroin be both classy and dirty at the same time? At once the line gives us a "basement room" away from the main floors and seemingly isolated and a needle and spoon and no doubt a dirty belt to tie the arm off. However, rather than giving us any colloquialisms referring to heroin, Richards and Jagger give us what I consider a classy allusion. This isn't Requiem For A Dream's traumatic sex scenes: it's Trainspotting's discussions on life and living.
Johannes' post has a great number of interesting points, including a section on Townes Van Zandt's cover.