I find that listening to fields and subliminals work optimally when lying on your belly with no pillow and arms either over your head like a rainbow or straight down close to body.
Especially if you are having headache issues/a lot of activity around forehead.
Also, if you are listening when lying on back, i recommend zero-two pillows maximum to rest your head and around four pillows under knee area where you can rest legs, let your feet slightly hang over pillows. Knees should be around 20cm above heart.
This improves blood flow/circulation, lowers blood pressure and minimizes lower backpain/legpain.