The following rule is very relevant today when some misguidedly believe that submitting to sex with spiritual teachers can help in their spiritual development.
Again, it was originally a lustful Ven. Udaayin who was the cause of this offence. This time, he suggested to a beautiful and devout woman follower that she make a special offering to him, that of sexual intercourse. The Buddha then set forth this rule:
"Telling a woman that she would benefit from having sexual intercourse with oneself is [an offence requiring initial and subsequent meetings of the Community.]"
(Summary Sa"ngh. 4; BMC p.117)
In full: "Should any bhikkhu, overcome by lust, with altered mind, speak in the presence of a woman in praise of ministering to his own sensuality thus: "This, sister, is the highest ministration, that of ministering to a virtuous, fine natured follower of the celibate life such as myself with this act" — alluding to sexual intercourse — it entails initial and subsequent meetings of the Community." (Sa"ngh. 4; BMC p.100)