[164] Now at that time a certain bhikkhunī, thinking, "The water ablution (udakasuddhikā) has been allowed by the Blessed One," while taking the water ablution too deeply, caused a wound in her private parts (muttakaraṇa). Then that bhikkhunī informed the bhikkhunīs of this matter. Those bhikkhunīs who were of few wishes … criticized, complained, and spread it about, saying: "How can a bhikkhunī take the water ablution too deeply?" …
"Is it true, bhikkhus, as is said, that a bhikkhunī took the water ablution too deeply?"
"It is true, Blessed One."
The Buddha, the Blessed One, rebuked them: "Bhikkhus, how can a bhikkhunī take the water ablution too deeply? This, bhikkhus, does not conduce to the confidence of those without confidence …
"And thus, bhikkhus, let the bhikkhunīs recite this training rule:
"When a bhikkhunī is taking the water ablution, it is to be taken to a depth of two finger-joints at most; for her who exceeds that, there is an offense of pācittiya."
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.