Here in North America, many trees and shrubs depend on birds to disperse their seeds. Berries are swallowed whole, the fruit digested, and then seeds are expelled away from the parent plant. This provided transport prevents the seeds from being in competition for water and light with well-established plants. A bird's digestive system also wears away some of the hard seed covering, improving its chances of sprouting once it reaches the soil. The relationship is mutually beneficial to both birds and plants, providing food for one group and increasing reproductive prospects for the other. Tonglen, a meditation of breathing in the suffering of others and breathing out with a wish for their comfort, is mutually valuable as well. For the person practicing tonglen, it loosens the ties of self-absorption, dissolves that feeling of separation, develops courage, and opens the heart. The person on the receiving end benefits too, though not through some magical lifting of their burden. Instead it comes through the compassionate, nonjudgmental focus of the practitioner, who doesn't run or attempt to avoid their pain.
I happened to be present one of the first times Tibetan meditation master Chögyam Trungpa sprang this bizarre sounding practice on an unsuspecting Western audience. One student of yoga had raised his hand and asked, with some bewilderment, why it wouldn't be better to imagine breathing in love and light and breathing out all negative impurities....Trungpa's unhesitating reply: “Well, then you'd just be like a polluting factory, taking in all these good resources and spewing out your gray cloud on everyone else.” ~ Marc Barasch
For more information on the seventh slogan, go here.