Its been a while since I was on rebif, so don't forget the salt with this post.
... I pull back on the plunger about one millimeter to keep liquid from exiting the needle tip (I read that on a thread here, but I can't remember which one, or who wrote it - thanks to whoever you are, it seems to work). Then I invert the syringe, tap it once lightly to make sure the air bubble is at the top, and proceed with the injection.
Maybe I have misunderstood what you have said. I am pretty sure that getting air in the syringe is a big no-no for intravenous injections, so I worked on the assumption that it wasn't the best for subcutaneous injections either. It sounds as if you would be injecting the bubble as well. I think I was shown to tap the bubble to the top and make sure I expel it before injecting.
The down side is that I have had to give up injecting in my arms since it takes two hands to do this method.
When i started rebif (a few years ago now, and stopped not to long after) they told me that injecting in the arms was no longer recommended. Personally, I heard the auto-injector go off without a syringe in it, and chickened out of using it. Its a little strange to me that people see this as the cowards way.
One to work the syringe and one to pinch up enough skin.
I'm pretty sure "pinching" the skin to inject into is also not recommended.
Again, I am no longer on rebif, so things could of changed and i could of been doing it wrong in the first place.