Tonglen reverses the ordinary self-protective habit. On the in-breath, one takes in the suffering of others — beginning, often, with someone easily imagined suffering. On the out-breath, one offers whatever is healing, spacious, or kind.
The practice trains something that cuts deeply against the grain: the willingness to be present to pain without flinching, and to give without counting cost. pema-chodron and Chögyam Trungpa have brought tonglen to wide Western audiences.