I have done this particular thing with, many horses. And it works GREAT! Lunge your horse before you try to get it in the trailer. When you lunge the horse it keeps there mind in the forward motion when you ask it to go in the trailer. When you do ask it to go in the trailer don’t use any blind folds or anything like that. Cause using blind folds is extremely dangerous. You may need just a short riding crop. When you ask, tap it on the butt until it moves then stop and keep doing this till its gets the idea that the trailer is a nice place. When you tap it on the butt increase the tapping till it moves. When the horse does smell the trailer or steps one hoof in the trailer STOP tapping. Ask any questions. I hope this helps!