[356] Now at that time, while a certain bhikkhu was performing a back-massage (piṭṭhiparikamma) for his preceptor (upajjhāya) in the bathhouse (jantāghara), semen was emitted. He was remorseful … "Bhikkhu, there is no offence, since you did not intend emission." Now at that time, while a certain bhikkhu, intending emission, was performing a back-massage for his preceptor in the bathhouse, semen was emitted … semen was not emitted. He was remorseful … "Bhikkhu, there is no offence entailing saṅghādisesa; there is an offence of thullaccaya."
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.