William Blake - Oberon, Titania, and Puck with Fairies Dancing (1786)
The promise? Unendurable pleasure indefinitely prolonged.
The practice that delivers on the promise? A simple, gentle in-drawn breath into the heart, with the feeling of unconditional love flowing out.
Don't let anyone charge you a fee for telling you this open secret. Don't even believe me although I offer it to you freely. Try it for yourself.
Of course, it will only deliver if you give ALL over to it. And you would have to be crazy to do that. But if you are that crazy, the results will astonish you.