"Give to the Bit" exercises are very beneficial for horses. There is a difference from Give to the Bit exercises and the Kiss the Stirrup.

Give to the Bit is more subtle, refined, and done with more finesse than Kiss the Stirrup. Look at it this way: KTS is like a child writing the alphabet in kindergarten, big and blocky; and GTTB is like high school college prep work :-). In the GTTB exercise, the horse (as well as the rider) are learning something. In the KTS, it is basically only a physical stretch for the horse. GTTB gives you and your horse more subtle communication, and better flexion for the horse.

These exercises can be done from the ground with any horse, including horses that have not yet been started. From the ground, stand next to the horse, just behind his shoulder, and take the reins, one in each hand, as if you were riding.

A bit is not necessary for these exercises. They can be done in a halter or sidepull. The Give To The Bit exercises could be called Give To The Rein since a bit is unnecessary.

The first point of GTTB is the mouth / jaw, at the corner of the lips. These are "baby gives" (more here about Baby Gives). You can take up your rein on one side, and slightly ask the horse to "give to the bit". Don't pull. A finger's worth of take up on the reins should be good. Wait for the horse to tip his nose, giving some slack in the rein, releasing the tension.

Immediately drop the rein! The "release" is what teaches the horse! If you are using clicker training, you can click and treat.

The first picture below shows the horse standing still, facing forward. Her ears are slightly back, listening, as she knows we're "working" on something, so she's paying attention. She is wearing a rope halter, sidepull style, no bit.

The next picture shows slightly picking up the rein, asking for a tip of the nose.

The last picture shows asking for more flexion, and the horse responds by bending the neck.

For a light and soft horse, they will pick up the feel on a loose rein; it is not necessary to have contact with a taut rein.