(copied from THIS link ) Imagine you have a friend small enough to fit in your purse or briefcase who will give you nightly massages, easing stress, fatigue, and muscle tension all for a onetime cost of about $3. Think yellow. Think tennis balls. The procedure is simple: place a tennis ball on a part of the body that is sore or tight and rest your weight on it. The pressure softens tight muscles and increases circulation. Dancers have long used tennis ball self-massage to work out their kinked-up muscles, and body workers frequently prescribe the practice for clients healing from chronic injuries. Asana practitioners searching for ways to increase flexibility and comfort in their bodies are beginning to get on the ball, too. Self-massage with tennis balls is greatly enhanced by stretching, which further increases circulation and reeducates the muscles to rest at a longer length. Combining asana with self-massage is particularly useful for those of us who have muscles that for various r