I recommend the following Gentle Stimulation of the Heart Chakra-Energy Massage found in A Handbook of Chakra Healing by Kalashatra Govinda:
1. Lie relaxed on your back with eyes closed. Activate your hand chakras by rubbing your palms together in a circle. Place the left hand palm down in the middle of the chest over the Heart Chakra and rest the right hand over the left hand. Take several relaxed breaths.
2. Deepen your breathing—especially the exhalation—for a short time. Imagine with each inhale, you are taking energy in, and that with each exhalation energy is pouring into your Heart Chakra.
3. Visualize radiant green energy in the shape of a ball or whirlpool filling your chest. Continue for the duration of seven breaths. Then rest your hands to your side.
4. Remain quiet for a short time so that you can feel the effects of this meditative practice. The author suggests making time for this brief massage at least once a day.