Chapter on Rules of Janabah and Methods of Purification

As for the narration reported by Muhammad ibn Ali ibn Mahbub, from Ahmad ibn Muhammad, from al-Husayn, from Faddalah, from Hammad ibn Uthman, from Umar ibn Yazid, who said: I said to Abu Abdullah عليه السلام: 'A man places his private part on a woman’s private part and ejaculates. Is ghusl obligatory upon her? Imam عليه السلام said: 'If any of the fluid reaches her, she should wash it off, but ghusl is not obligatory upon her unless penetration occurs.' I said: 'What if she ejaculates, but penetration does not occur?' Imam عليه السلام said: 'Ghusl is not obligatory upon her.'"