Tonglen is a Mahayana practice of love and compassion. Love is wanting all sentient beings to be happy. Compassion is wanting all sentient beings to be free from suffering. In order to make these concepts love and compassion more personal, to help them become more experiential than just conceptual, we practice exchanging self for others. Tonglen is also known as sending and receiving. The practice involves visualizations and is intended to open up our hearts to others.