The level of trance you achieve depends greatly on your relaxation, concentration skills and will power. To enter a deeper trance, i.e., Theta level and beyond, you have to concentrate much more and for much longer, on the mental falling sensation aided by breath awareness. The first level of trance, i.e., when you get very heavy, is quite deep enough for projection. I strongly advise against forcing yourself deeper than a light trance, until you have plenty of experience with the trance state.
How can you tell if you are entering a deep trance? There are four very noticeable symptoms:
1. An uncomfortable feeling of cold that doesn't make you shiver, coupled with a steady loss of body heat.
2. Mentally, you will feel very odd and everything will feel extremely slooooow. Your thought processes will slow down as if you had been given a strong pain killing injection.
3. You will feel disassociated from your body, i.e., a strong floating sensation and everything will seem far away.
4. Total physical Paralysis.
Note: These four things, ALL TOGETHER, signify you are entering a deep trance.
Do not mistake the mild floating sensation you sometimes get with light trance, i.e., as you astral body comes loose. Or the slight loss of body heat from sitting still for a long time and the mild paralysis, i.e., the heaviness, for a deep trance. The sensation of deep trance is quite uncomfortable and unmistakable for what it is.
It is very difficult to get into the deep trance state, as you need highly developed relaxation, concentration and trance state skills plus lots and lots of will power and mental energy. You will not accidentally fall into it.
If you are worried you are going too deep, remember this:
You CAN pull yourself out of it at any time. Concentrate ALL your will on moving your fingers or toes. Once you can move a finger or toe, flex your hands, move your arms, shake your head, i.e., reanimate your body; and get up and walk around for a few minutes. Falling into a deep trance should not be a problem with these exercises.
I have seen many people in meditation groups etc, enter a light trance and not be able to pull themselves out of it, i.e., they float away with the faeries. Usually some kind person will talk them out of it or massage their wrists etc to get them to come back to reality. This is unnecessary and is the result of lop- sided training, i.e., no concentration or will power training. The person only THINKS they cannot come back and therefore does not try very hard. It is also a good way of getting attention from the group.
Note: Your mind is extremely powerful and has vast untapped resources. It can do ANYTHING, no limits, if it is trained, conditioned and properly motivated.