Tissametteyyasuttaniddesa

Suttapiṭaka · Khuddakanikāya · Mahāniddesa · Vol. 29 · Section 258

[258] **Should not indulge in sexual intercourse** (na nisevetha methunaṃ): what is called sexual intercourse (methunadhamma) is that practice of the ignoble (asaddhamma) … ; for that reason it is called sexual intercourse. One should not pursue, should not indulge in, should not cultivate, should not engage in sexual intercourse — hence, "should not indulge in sexual intercourse." Therefore the Blessed One said: Having known this danger (ādīnava), the sage (muni), with regard to the before and the after here, should make his solitary faring firm; he should not indulge in sexual intercourse.

English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.