While galloping away on my little horse, my saddle slipped! It completely slid under my horse, me falling off with it. That's the second time it's happened, and though it hasn't happened again for a while, I'm still afraid it will happen and I don't quite know what caused it to slip. I saddled up my horse normally, and I might have put it a little too loose, but I was constantly checking it making sure it wasn't. A family friend suggested that my horse "blows himself up" (holds his breath)..how can I prevent this from happening again? Thank you!