Often it tends to fade to black, and there will be a transition period of a few seconds where I seem to be floating in empty space before I wake. Sometimes it's too short to react to, but often this gives me an opportunity to spin in order to try and prolong the dream. Sometimes I get back into the dream and other times get weird things happen, for example, once I had a vision of strange bright patterns that looked almost like red stainglass windows against a totally black background that slowly changed to green from the centre, whilst I could hear Shpongle's "Behind Closed Eyelids" track playing in my head.