Mahabharata 13.148.21

न नग्नामीक्षते नारीं न विद्वान्पुरुषानपिमैथुनं सततं गुप्तमाहारं च समाचरेत्

na nagnāmīkṣate nārīṃ na vidvānpuruṣānapimaithunaṃ satataṃ guptamāhāraṃ ca samācaret

Our plain-language meaning of this verse is waiting for scholar review.