I was interested by this topic when I first saw it and since no one has replied I will give a breif answer. I have felt some spillover from the 2 states for a few minutes a couple of times and I was thinking that if cultivated this would lead to the "phasing" method, where you could go into the astral without the traditional obe. I think this is being discussed in the astral conciuosness forum.
My body was no longer tired, and so I slowly awoke/shifted consciousness from the astral to the physical. However, I was aware that I still had some unfinished business in the astral. I had a meeting with a person, whom I had had a strong longing to meet again, the night before I went to sleep.
So, I let my physical body get up and out of bed, getting ready for the day. Meanwhile, I maintained my astral presence. We both sat in meditation posture. The subject "discussed" was physical (lower chakra) vs. spiritual/heartfelt love. During the "discourse", I could feel heart chakra love, in my astral body - which in turn reflected to my physical body (or perhaps the other way around ?). It was quite invigorating in any case.
I had some difficulty in making sure that my physical body's surface mind thoughts did not spill over into my astral presence. But I succeeded reasonably well - as far as I was able to perceive. After the main goal of the meeting had been accomplished, I saw that I was no longer able to maintain my astral presence for much longer. I forcibly withdrew my astral presence. The meeting had ended.
Has anyone here tried to maintain a physical as well as an astral presence at the same time ? (my belief system demands a few reality checks from time to time)