One cannot envision contact; so there are no images accompanying this post. One can, however, conceptualize contact. To get the concept, enlist someone else to read these words while you sit on a saddled horse, without stirrups, eyes closed. Then pick up your stirrups, and listen again, eyes closed.
Obtaining and maintaining soft contact- that is contact with the leg, seat and reins is a complex, and, I dare say, crucial concept of equitation. Contact entails, on the part of the rider, an awareness of his calves and –through his boot and saddle flap– a “feel” of the side of the horse. Simultaneously, the rider must be aware of the inside of his thigh, his seat bones, and lower back, and– through the saddle flap, the seat of the saddle, and the pad underneath it– “feel” the horse’s back. Also simultaneously, the rider must be aware of his own shoulders, elbows, wrists, and fingers, and –through his gloves, reins, and bit– the horse’s neck and head to “feel” of the horse’s mouth. It is all to be connected.
Actually, it is more complicated than that, or vastly simpler, once you understand that what we really want to do is feel, in order to control, the horse’s individual hind legs, prerequisite to controlling the horse’s back and shoulders. Which is why it is more apt to say that we “put the horse in front of the rider’s leg” than to say that we “put the horse on the bit” as an indication of a more intense, more energized degree of “riding on contact”.
Now, if all of this is complicated for a rider, who is, after all, a human being possessed of intelligence superior to the horse which, partner though it may be, or is becoming, is still an animal, then learning to go “on contact” is immensely more difficult for a horse. The horse must have that identical set of awarenesses, albeit in reverse, and must submit its animal will to its “feel” of, i.e. awareness of stimulation by, a rider. So be sympathetic, and question yourself, first, if things are not going well.
More specifically, recheck the correctness of your overall position, and your position’s ability to fluidly follow and absorb the motion of the horse, without, in any way, interfering with the balancing gestures of an equine athlete at any stage of development. To do this, it is wise for riders, whether novice or vastly experienced, to develop or refurbish their own seats and “feel” for contact by riding schooled horses alternately with green prospects.
Whether riding a green or schooled horse, the mechanics of putting the horse “on contact” are the same. And perfecting the process of obtaining and maintaining contact with a horse is a lifetime quest…more on this later.