Mahabharata 12.318.20

अन्योन्यं समभिप्रेत्य मैथुनस्य समागमेउपद्रव इवाविष्टो योनिं गर्भः प्रपद्यते

anyonyaṃ samabhipretya maithunasya samāgameupadrava ivāviṣṭo yoniṃ garbhaḥ prapadyate

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