PārājikkaṇḍaPaṭhaṁpārājikasikkhābada

Vinayapiṭaka · Bhikkhu Vibhaṅga (1) · Vol. 1 · Section 52

[52] Now at that time a certain bhikkhu, thinking, "In this way there will be no offense (āpatti) for me," having become naked, engaged in sexual intercourse (methuna dhamma). He had remorse (kukkucca) … "Bhikkhu, you have committed an offense entailing defeat (pārājika)."

English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.

This passage also appears in 5 other places