slow is the way to go. Did you ever stick the needle all the way in and then let go of the syringe and have it "angle" to the side? What you thought was a 1.5 in injection really turns out to be a .5 in injection. When you go slow, you can let go of it as you are pushing it in and make sure it is going straight. Plus, whether you are going fast or slow, if you are going to hit a nerve you are going to hit it - so I'd rather feel it slowly so I can retreat and move over . . . can't do that when you rush it.