Instead of lengthening the reins
To fire off a horse’s back. Begin with caps, and, by degrees, as with
the drum, instead of lengthening the reins, stretch the bridle hand to
the front, and raise it for the carbine to rest on, with the muzzle
clear of the horse’s head, a little to one side. Lean the body forward
without rising in the stirrups. Avoid interfering with the horse’s
mouth, or exciting his fears by suddenly closing your legs either before
or after firing be quiet yourself and your horse will be quiet. The
colt can learn, as I have already observed, to bear a rider on his bare
back during his first lessons, when prostrate and powerless, fast bound
by straps. The surcingle has accustomed him to girths he leads well,
and has learned that when the right rein is pulled he must go to the
right, and when the left rein to the left. You may now teach him to bear
the BIT and the SADDLE if you have not placed it upon his back while on
the ground, and for this operation I cannot do better than return, and
quote literally from Mr. Rarey.
Fonte: Tamming Horses