Mujahid (may Allah have mercy on him) said: People used to avoid women during menstruation, but they would approach them from the back (i.e., have intercourse with them). They asked the Messenger of Allah (peace be upon him) about this, so Allah the Exalted revealed this command: "They ask you about menstruation. Say: It is a harm, so keep away from women during menstruation, and do not approach them until they are purified. But when they have purified themselves, then go to them from where Allah has permitted you." [بقره: 222/2] He said: The meaning of «﴿مِنْ حَيْثُ أَمَرَكُمُ اللَّهُ﴾» is to use the vagina and do not go beyond that.