Instructions
Place the crop in your left hand (the hand holding the reins) as you mount your horse.
Sit comfortably in the saddle, placing both feet in the stirrups and pick up your reins in both hands, making sure not to hit your horse with the crop.
Hold the crop in the palm of your left hand with the first three fingers of that hand wrapped around the handle. Pick up your left rein with the same three fingers and do the same with the right rein in your right hand keeping both "pinkie" fingers free underneath your fist.
Position both of your hands close to your horse's withers, keeping them at hip-width distance apart with the thumbs on top and your wrists perpendicular to your legs. There needs to be a direct line between the horse's mouth and your elbows. The end of the crop should be horizontal and close to your left leg.
Keep the crop in the same position as you begin to move your horse forward. To avoid pulling on your horse's mouth, take both reins in one hand when you want to use the typical jumping crop on your horse with the other hand. A dressage whip is long enough not to require you to take your hand off the reins if it is angled correctly across your thigh.
Switch the crop back and forth to whichever hand is your "inside" hand as you ride--in an arena, this would be the hand on the side of the horse away from the rail.
How to Carry a Crop When Riding English
English riding crops are short, leather-covered sticks used as an aid in horseback riding--usually the hunter-jumper and eventing disciplines. Wielded by riders as an extension of the leg while in the saddle, crops for adults are usually 20 to 24 inches long with a rubber or leather-wrapped handle and a short leather loop on the end. Children's crops may be shorter. Dressage whips are a longer variation of the riding crop; the U.S. Equestrian Federation rules state that they may be no longer than 43.3 inches when used in dressage competitions. The handles are normally made of metal and they end in a single, nylon string. Because crops are considered "artificial" aids, they are not usually recommended for new riders learning how to guide a horse with their body.