When we encounter suffering, we can practice exchanging oneself for others; when we experience happiness, we can also practice exchanging the self for others.
From a mundane standpoint, we are enjoying our happiness when we have good health and material comfort; but from a liberation standpoint, we are wasting our blessings and happiness. In the sutras, the teachings remind us over and over again not to waste our happiness. Hence, when we are successful in our career or feel great joy in life, we must practice exchanging the self for others.
As we breathe out during meditation, visualize our happiness and the causes of this happiness — the virtuous actions and merits of the past, present, and future — transformed into a white gaseous substance which is then dissolved into the minds and bodies of all sentient beings. Visualize all sentient beings receiving this happiness and its causes, and thus being free from suffering.
- Quote from Are You Ready For Happiness? Don't Let the Paper Tiger Scare You Off, "How to Face Happiness"