Here's the best way to do it.
Prepare it the same way that you would to IV, and filter the solution the same way (you must use a syringe to make sure there are no particles that passed through the filter).
Then you take your belt off and tie it around your arm, you stick the needle in your vein and then you pull back. If you don't see blood but you're pretty sure the needle is in the right location on your arm, push it in or pull it back a little bit because you might have punctured too deep and gone out the other end of the vein, or you may not have punctured deep enough. Sometimes right when you stick the needle in, your veins shift over to the side and you end up breaking the skin but not entering the vein at all. In this situation, you don't want to take the needle out and go stabbin again, but rather maneuver it within your arm and try and catch the vein.
The rumors about bubbles killing you instantly, or not shooting in the exact direction of your heart killing you instantly are total bullshit. Mind you, I shoot some of the best dope in the USA (PATERSON NJ, PTOWN BABY!) and it's not tar, but I'm pretty sure it works the same way.
Trust me bro, you're doing heroin. You're basically already a dope feind, you may as well just start economizing and shooting dope. Tell any non user "I do heroin but I don't inject it so it's okay" and see what they say. Not trying to come off as harsh, I just don't understand why a well-informed, intelligent sounding user like yourself wouldn't IV.
-Exoskeletal, junction at the railroad dela-