A hypothetical Sleep Stack (list of audios that may help with preparing you for sleep and during sleep) is here.
Sweet Dreams is meant for use during sleep.
Lucid Dreaming can be looped while sleeping if you would like vivid or lucid dreams.
Utter Relaxation and Muscle Massage can be looped while sleeping if desired.
Positive Energy can be looped while asleep for more pleasant dreams.
At the bottom of this article it mentions about audios being looped while asleep:
“An extra trick you can do is leave a field on auto repeat all night beside your bed. As long as your conscious mind can sort of hear the field, it will still continue to work for you all night. If you have a field in an item, you could place it under your pillow. Having these fields work for you in your sleep will help make these changes happen at an even faster pace than you’d imagine. Although this works, sometimes the energies will not allow you to sleep. You can download the ListenOnRepeat app on android or iPhone and have the audio playing all night or create a playlist on youtube that has the same audio for the amount of time you’ll be asleep.”