Let's try a little evaluating some possible explanations of a couple of data points. Suppose 2 people were placed in separate isolated chambers and went into an assisted state of mind that was subjectively unique. If it helps, we can start by calling it body asleep/mind awake. While in this state these individuals experience the same things at the same time (meet each other, meet others, travel to places together). Their respective experiences are recorded verbally while in this state allowing playback and verification. The recordings show the overlap and simtanaity in time.
Another two individuals (a man and a woman) are placed in the same state in isolated chambers and they meet in a non-physical way. They have what might be termed etherial sex. While there are similarities to intercourse, the depth of the experience far exceeds anything achieved through traditional intercourse. There are other subjective components that are unique. After returning to normal waking state, they compare their respective experiences and find complete agreement as to their shared experience.
Let's assume these two examples are replicatable experiences. While not everyone can easily experience things like this, enough people are able to do so with some practice that the results don't seem to be simple anomalies. What explanations come to mind as to the nature and cause of these observable/replicatable phenomena?