It sounds like he's describing lucid dreaming, although with lucid dreaming you don't induce simply a "happy dream", you induce a hyper-vivid dream that you can completely control. if you want to practice your piano skills, you can during a lucid dream and use your dream practice in a waking state. if you want to fly or breathe underwater, you can. if you want to see belldandy naked, well, that can be done too. there is no limit to how you can control your dream and lucid dreams are in near real-life clarity. i mentioned this on another thread but it seems appropriate to post this here too. here is a link with some induction techniques listed if you are interested in trying this:
http://en.wikipedia.org/wiki/Lucid_dreaming
30-Nov-2006