It is all right to fall asleep while listening to a Paraliminal as long as your intention is to get benefit from the tape, and you happen to fall asleep.
If your intention is to fall asleep you might only receive the relaxation benefits of the program.
Nightmares, etc? Not likely. A tape can stir stuff up, so... Usually people will have a better night sleep after listening to a Paraliminal before bed.
