I`ve only done this once,a few years ago when there was a full moon (anyone give credence to lunar and planetary influence of dreams as in intensity ect ?)and at the time it seemed like the easiest thing in the world. I was just falling asleep and I got a fairly vivid image of the street just outside my house on a sunny day.So I gently put myself into the picture in the 3rd person performing the tactile sensation of rubbing my hands together.Then whoosh - straight in - full lucidity.Detail was perfect.lasted for about 5 minutes before I lost it and woke.