Aware of sunshine, trees, drifting clouds through window on my right. Sitting at computer. Hand on mouse. Doing something or going somewhere online. focused attention. Eyes close. Instantly inside a dream narrative that has the feel of having been going on for a while, though not always (so far as I can tell) the same narrative. Defuse attention. How long? A few seconds to a minute best estimate. Wake up. Dream narrative unavailable to consciousness. I can do this many times over the course of an afternoon hour. The affective color of this experience--conscious & unconscious parts taken together--is neutral to mildly pleasant.
Note: About ten years ago, while taking a prescribed sleep drug, I had a couple of frightening, anxiety-inducing experiences in which I felt myself to be simultaneously asleep & awake. That is, I was doing something in waking life while at the same time doing something else entirely unrelated in a dream or dream-like state of mind. (These experiences took place during the daytime, when the zolpidem was supposed to have cleared my system.) The "double exposures" had a dark, negative affect, even long after they had passed & I was merely recalling them.