The following extract is taken from the book 'Asana, Pranayama, Mudra, Bandha' by Swami Satyananda Saraswati.
Yoga Danda (breath balancing stick)
The yoga danda is a special T-shaped stick traditionally used by yogis as an aid to meditation. The horizontal beam rests firmly under and supports the armpit with the bottom of the vertical stick on the ground. When the breath flow is equalized, the danda may be placed in front of the body. Both elbows may be rested on the horizontal beam with the arms folded or in any other position. The yoga danda may be used for long periods of time without the arms becoming tired.
Benefits
The pressure under both armpits helps to open the nostrils to facilitate the practice of pranayama. Since the breath flow in the right and left nostrils influences the activities of the sympathetic and parasympathetic nervous systems respectively, opening of the two nostrils induces a state of autonomic balance.
As with all yoga practices, it is best to receive instruction and guidance from an experienced teacher.
www.yogamag.net/links.shtml has a list of Satyananda yoga centres worldwide, where it is possible to receive training.
