Extending loving kindness meditation from the primary practice of ourselves and a chosen easiest being, we can open at times to include any dear friend whom also easily come to mind. At this stage of practice we are inclining out mettā practice to rest where mettā is easiest. This would be any beings for whom it is easy to see the good in them, and we easily feel warmth.
What is special about a 9-day Loving Kindness retreat? The form of Buddhist practice helps cultivate positive qualities of friendliness and kindness, it helps purify old habits of defensiveness and hostility, and it help cultivate samadhi (concentration).