Acelakavagga

Vinayapiṭaka · Parivāra · Vol. 8 · Section 334

[334] A bhikkhu engaging in sitting together with a woman (mātugāma) in private, on a concealed seat, commits two offenses (āpatti): as he is sitting down, there is an offense of wrong-doing (dukkaṭa) for the effort; when he has sat down, there is an offense entailing expiation (pācittiya).

English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.

This passage also appears in 1 other place

Vol. 8 · Section 320 — Ovādavagga