Srimad Bhagavatam Canto 06, Chapter 18, Text 51

SB 6.18.51

nadhauta-padaprayata
 nardra-pada udak-sirah
sayita naparan nanyair
 na nagna na ca sandhyayoh
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
You should not lie down without having washed both of your feet or without being purified, nor with wet feet or with your head pointed west or north. You should not lie naked, or with other women, or during the sunrise or sunset.
Srimad Bhagavatam Canto 06, Chapter 18, Text 50
Srimad Bhagavatam Canto 06, Chapter 18, Text 52