I'm a huge believer in Fascia Stretching... By doing Biceps and Triceps on the same day you get the best results. Dogg Crapp, FST-7 and others focus on Stretching the Fascia in one way or another.
By Super setting your Always pumping more blood into both sides of the Arm. This keeps a better force of Stretching the Fascia. The more you get it to stretch. The easier your muscle will grow and fill out.
If you don't super set Biceps and Triceps... Do triceps first. No matter what. If not. After your have a good pump on your Biceps. You CAN NOT get a good contraction on the triceps.
I'm no Mass Monster, but this has worked well for me and my wife..