Sacking out
![Desensitizing an otherwise trained horse to accept the fluttering skirt of a lady's riding habit.](/Images/godic/202502/08/Horsemanship_for_Women_0563444.png")
- The phrase "sack out" also refers to going to sleep.
Sacking out is a method used by horse trainers to desensitize a horse to potentially frightening situations or objects. It is a process that, done properly, teaches a horse to not fear certain objects or situations, and, over time can be used to teach a horse to stop and listen to its handler in any potentially frightening situation, thus, in effect, to assess the situation instead of immediately acting upon its fight or flight instinct.