Definitely agree with the folks that said any semi-long-term user would be able to manage playing all night without nodding out, especially if you don't continue to increase dosage too drastically. After using regularly for just a few months, a lot of people don't get much of a high aside from the very initial buzz, if they are even lucky enough to feel that. For most in the midst of addiction, it's usually just a fix to feel "well" and be able to function without withdrawal symptoms. In the same vein (lame pun intended!), when many people first start using opiates, they actually get more of a euphoric rush that can keep them up all night, make them more social, and so on. That's how it was for me, anyway.
I also used to wonder about how he was able to shoot up, and wondered if he did indeed have someone do it for him, but others have brought up some very good points that could make a lot of sense, although different techniques work for different people, depending on the type of veins you have, which veins you're using, what kind of shape the veins are in (scar tissue, etc.). I know way too many people who got to the point where they had to shoot up in the most absurd places due to veins that were in horrible shape after years of abuse. Even the most skilled doctors/nurses were unable to draw blood and/or find a vein for IV medication (i.e. anesthesia, sedatives for surgeries, etc.). It's pretty bad when you can see and feel a vein and you're literally in that vein, but blood just will not come out anymore, sometimes for years....
Well, I wish I had something more positive to end with, but I don't. Oh..happy Friday!!...??