In the Tibetan tradition, they use the breath to develop compassion: You breathe in the suffering of the world, you breathe out compassion for other beings. Breathing in friendliness to yourself; breathing out friendliness to others. Breathing in – forgiving yourself; breathing out – forgiving others. Please try this. Because if you can develop this association, if you can make such a connection, then the breath will always be associated with loving-kindness.
That can be another very positive aspect of our friend the breath: whenever you think of your friend, loving-kindness arises. You can have loving-kindness for yourself, and you can have loving-kindness for others. See how the polarity can again be used functionally.