This practice is the first of the Four Protective Meditations, which show us the potential as well as the limitations of a human life. These are reminders of what is true, real and possible.
Guided meditation on the water element, internally and externally, and meditating "like water" so "arisen agreeable and disagreeable contacts will not invade the mind and remain."
Using the Buddha's advice to his son, Rahula, on developing different types of meditation, starting with meditating on the earth element internally and externally, and meditating "like the earth."