Sit somewhere quiet where you can be alone and undisturbed. This exercise can be done either with your eyes closed or else open and resting on a simple object such as a flower or candle flame.
Focus exclusively on your breathing. Slow your breath and make the flow of breath as calm and controlled as possible. Imagine that someone has placed a tiny thread right in front of your nose: focus on that thread and ensure it is absolutely still and unwavering.
When your breath is calm and controlled, please imagine that what you are breathing in is not air, but joy: pure, unalloyed joy.
This joy is not associated with any particular incident or experience in your life: it is the pure essence of joy, the inner thrill that accompanies the experience. Enter into and expand this inner thrill, allow it to permeate your consciousness.
As you breathe out, exhale the opposite of joy, which is sorrow, sadness, depression: any negative thought or feeling.
Feel this joy, this bliss circulating within you, percolating throughout your whole being, charging every cell of your existence with a current of delight.
Feel this joy welling in waves from your heart, blazing like the sun in all directions, flooding everything and everywhere. Feel pure bliss beaming through your smile, radiating from your eyes, shining within and around your face and your whole being.
If you were to stand outside of yourself and look back at yourself, or gaze into a mirror, you would see the most beautiful, radiant being of bliss.
This bliss, this delight flows unendingly seemingly without a source and knows no boundary, no limit, beyond time and space. Feel that you are first flying in an unhorizoned sky of bliss: then you become that ever-expanding sky.