This slogan refers to our general tendency to dwell on pain and go through life with constant complaints. We should not make painful that which is inherently joyful.
At his point, you may have achieved a certain level of taming yourself. You may have developed the tonglen practice of exchanging yourself for others and feel that your achievement is real. But at the same time, you are so arrogant about the whole thing that your achievement begins to become an evil intention, because you think you can show off. In that way, dharma becomes adharma, or nondharma.
From Training the Mind & Cultivating Loving-Kindness by Chogyam Trungpa , copyright 1993 by Diana Mukpo.
(Official Chogyam Trungpa Website)
Published by arrangement with Shambhala Publications, Inc., Boston.
This site provides an on-line database of commentaries on the Tibetan Buddhist meditation practices of lojong (Mind Training) and tonglen.