Sleepsurfing is a unique state of consciousness in which the state itself cyclically fluctuates in a gentle wavelike manner in and out of sleep as shown above. Sleep is consecutively entered and exited in positions A as consciousness just barely emerges from sleep and in position B as consciousness dips lightly into sleep. Cycles may have a frequency of every few seconds to a minute or so, something not easily gauged exactly but you recognize them as you experience them. An accompanying mild euphoria that one sometimes feels for a short time upon awakening from a very good sleep can be extended and repeated many times during sleepsurfing.
With some practice under the right conditions you can surf many cycles to ride for a long time in a kind of active meditation process. During each gentle cycle you have an opportunity to observe transitional events in your consciousness that you may have never noticed before as they went by so suddenly and usually just once at a time. In particular you repeatedly cross the sleep/wake threshold (A's above) and have many opportunities to study your consciousness popping up again and again out of sleep. Except after a while you notice that it doesn't really pop up so much as fade in over a short period of time. During this time there is a switchover from an internally generated sleep sensorium to external inputs binding to consciousness, and if all the conditions are right for it you may be able to detect an artifact of the binding of the auditory system to consciousness at that time. See the Auditory Binding Experiment for more detail about that if you're interested. Sleepsurfing is a requirement for detecting auditory binding, but even if you don't detect it, sleepsurfing is an interesting state of consciousness to explore.