Is it possible to be stuck in deep trance?

[Gbob]

A few times I've been attempting to project. I just lay there for 40 minutes trying to get into a deep trance. I don't try any techniques as I just want to naturally exit my body. But it never happens, it just feels like I'm stuck in this deep trance state. I then try some techniques: sometimes there are vibrations but they quickly subside. What's going on?

[Xanth]

Nope, not possible to get stuck in a Trance.
Because the moment you start thinking about anything physical, your attention gets drilled back to your body.

I can pretty much guarantee you that your problem is not relaxing enough.
There's gotta be some point on your body that isn't relaxed.
For me personally, it's my head... REALLY hard to get the muscles to stop tensing.

[CFTraveler]

I agree with Xanth.

[Gbob]

So say if I were really relaxed mentally and physically, theoretically would I just naturally slip out of my body? Or does it depend on some other factors as well?

[kurtykurt42]

You would fall asleep after enough hours in trance. I can go for about an hour in deep trance, then I don't feel like dong it anymore.

[CFTraveler]

So say if I were really relaxed mentally and physically, theoretically would I just naturally slip out of my body? Or does it depend on some other factors as well?

Not always.  Sometimes, as Kurt said, you'll fall asleep, missing the experience.  Even if you stay in trance you probably will have to perform an exit technique, since your etheric body doesn't automatically exit just because you stayed in trance.
I notice you said 'I tried to exit naturally', but the thing is, that when you project in your sleep, you don't remember it, because 'naturally' means 'fall asleep'.  That's why there are exit techniques- to train the mind to stay awake at the optimal time, and to train your consciousness to accept the separation and still stay asleep.  Conscious projection is the result of chance (something wakes you when you would naturally would be unconscious) or training, and that's why we opt for training.