The practice begins with oneself or a loved one experiencing difficulty. Breathing in, imagine absorbing their pain as dark smoke or heavy substance; breathing out, send relief as light or healing energy. Gradually expand to include difficult people, strangers, all beings.
This reversal confronts ego's primary concern with self-protection and comfort. By deliberately taking in what we normally avoid (suffering) and giving away what we cling to (happiness, ease), tonglen loosens self-centeredness.
Pema Chödrön teaches tonglen as antidote to isolation. When suffering, instead of feeling alone, we recognize millions share this experience. Taking in their suffering connects us; sending relief extends compassion. We transform personal pain into catalyst for universal compassion.
The practice seems counterintuitive—won't absorbing suffering harm us? Teachers explain that fear itself causes more harm than the practice. Moreover, meeting pain with compassion rather than aversion actually reduces suffering.
Tonglen embodies Mahayana Buddhism's bodhisattva ideal: the willingness to take on others' suffering for their benefit.
Source
Tibetan Buddhist Tradition