If you are injecting into the glute, I think it is pointless to pull back. The glute is a muscle that does not contain many viens, and when was the last time you got a shot at the doctor? Did they pull back??? No, they didn't, because there is really no reason for it. That is why they give shots in your ass. Now, injecting into a quad, yes I would pull back, since it is a muscle group packed with viens. I think for begginers, pulling back is just going to confuse them. First time injections are not going to be smooth b/c of an itchy trigger finger. If they found a little blood (likely) they would toss the perfectly good gear? Aspiration is an issue blown way out of porportion. That is my 2cents. Flame me if you want, but I think it is wasted effort. Just shoot it and be done with it.