There are 3 kinds of releases in jumping (not just hunters). one is a long release, two is a short release and three is a automatic release. A long release is when you give more slack in the rein. A short is when you give just a little slack. An automatic is when you keep a light contact with the mouth and is considered more advanced. Most important is to focus on balance and not release. A release is something that will happen naturally if your balance is good and your arms are relaxed. The horse then moves your body the way it is supposed to. People do way too much when they jump. The horse is doing the jumping not the rider.