From: Horse Training Equipment
Draw reins are an extra pair of reins which the rider holds. They act by encouraging the horse to work in an outline.
Draw reins were invented by William Cavendish during the 16th Century.
Draw reins act on the bars and corners of the horses mouth and exert a downward pressure on the poll which subsequently encourages the horse to flex from the poll and lower the head carriage.
With sufficient leg and seat from the rider the horse will learn to engage their hindquarters and work up into the bridle where the riders light hand will support the contact.
An experienced rider will be able to encourage the horse to work through their backs and lower their necks to help with the horses suppleness and to reduce tension throughout the horses body.
Holding The Reins
In each hand the rider will hold their snaffle rein as usual going between the ring and little finger and then across the palm where they are held in place by the thumb and first finger.
The Draw rein is then taken up under the little finger and across the palm where it sits on top of the snaffle rein and is held in place by the thumb.
The rider can then gently squeeze the draw rein with their little finger and also have the safety that the thumb can release of the rein.
How To Use Draw Reins