In recent thinking and training, I've come to realize something regarding inexperienced "knifers": that they tend to back you up against something to bulldog you with stab after stab. Once they get you backed into a wall, corner, or other obstacle, you can pretty much kiss your butt goodbye. The off hand will be pinning you and their knife hand will be sending your soul to the afterlife. So, when you're training, make sure that you have the ability to move out of these situations and how to not get yourself backed in in the first place.