Usually my SP consists of a total sort of clarity. I don't feel any energy waves, or hear any specific sounds though. All my senses are esentially normal aside from occasional flashes of dreams. They seem to be triggered by outside stimuli.

I fell asleep in my car at Walmart once, and woke up SP'd, and at first I just focused on being concious, and I could hear people talking as they got in the car beside me and drove away. Then I lost focus, and when a woman nearby started talking, I dreamt that I was sitting in a chair having a drink with my old kindergarden teacher and a friend of hers laughing it up. Suddenly they started to drift away as reality returned, and I remember purposefully making myself say "Hey, can you hear me? Hello?" and by the time I said hello in a raspy voice, I shot back to reality (though still in SP) as someone walked by my car, so I probably scared the crap out of them.