It is not permissible to have sex with a woman in her anus, nor during her menstrual period, nor when she has post-natal bleeding. Indeed, this is one of the major sins. When they become purified by complete ablution (ghusl), it is permissible for the husband to have sex with her in the way which Allah commanded. That is to have sex with them in front (i.e., the vagina)... As for the anus, it is a place of harm and feces, and it is not the place for planting seeds [sic]. Therefore, it is not permissible to have sex with the wife in her anus. So it is incumbent upon all the Muslims to be on their guard against this sinful deed, and it is necessary for the wives to avoid it, and not allow their husbands to commit this great sin. That is, sexual intercourse during the menstrual period, during post-natal bleeding, and sex via the anus.