So it took me pretty much the entire weekend to settle on an appropriate song that I feel encapsulates the feeling of being cradled by a drug in both the melody and lyrics (stemming from my own similar experiences a couple years ago). I at first looked up blatant heroin based songs, but they all seemed a bit too obvious.

"Object" by Ween
This song's lyrics are somewhat ambiguous in meaning, as the song is generally considered to have one of two possible narrations:
1) It is a murderer singing to/about a recent woman he killed.
2) It is a first person dialogue in which a man is talking to his penis with intent to circumcise himself.
In either case, I don't imagine that those narratives would be conveyed when meshed with visuals of a drug-related nature - the major emphasis being placed on the repetition of the word "object."

Other possible song choices I generated include:
"Walk on the Wilde Side" - Lou Reed
"Symphony No.7" - Beethoven
"Most of the Time" - Bob Dylan
"Garlands" - Cocteau Twins
"Alone" - Colin Newman
"Atlantis" - Donovan
"Needle in the Hay" - Elliot Smith
"Time to Pretend" - MGMT

Inspiration for this mood, feeling, etc, is from a particular scene from "Trainspotting," in which the main character and narrator, Renton, experiences his first heroin overdose - left completely helpless and at the mercy of his habit. I couldn't find this clip in English, but this dubbed version should suffice. And here are a few stills from this scene of inspiration for the sequence/color palette.