[253] **Then again, engaged in sexual intercourse (methuna):** what is called sexual intercourse (methunadhamma) is that practice of the ignoble (asaddhamma) … For that reason it is called sexual intercourse. **Then again, engaged in sexual intercourse:** at a later time that bhikkhu, having repudiated the Buddha, the Dhamma, the Saṅgha, and the training (sikkhā), and having reverted to the lower life, is engaged, occupied, applied, and thoroughly engaged in sexual intercourse. Hence: "then again, engaged in sexual intercourse."
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.