One should never sleep in a naked state. One should never even touch the remnants of other people's dishes and plates. One should never, while he is in an impure state, touch another's head, for it is said in the scriptures that the vital airs are all concentrated in the head.
स्वप्तव्यं नैव नग्नेन न चोच्छिष्टोऽपि संविशेत्॥ उच्छिष्टो न स्पृशेच्छीर्षं सर्वे प्राणास्तदाश्रयाः।