Praise be to Allaah.

Having intercourse with one’s wife in her back passage is a major sin, which the Prophet (peace and blessings of Allaah be upon him) mentioned in conjunction with going to fortunetellers, and he described it as kufr. He (peace and blessings of Allaah be upon him) said: “Whoever has intercourse with a menstruating women, or with a woman in her back passage, or goes to a fortuneteller, has disbelieved in that which was revealed to Muhammad (peace and blessings of Allaah be upon him).” Narrated by al-Tirmidhi, 135; Abu Dawood, 3904; Ibn Maajah, 639. classed as saheeh by Shaykh al-Albaani in Saheeh al-Targheeb, 2433. 

The Prophet (peace and blessings of Allaah be upon him) cursed the one who has intercourse with a woman in her back passage and said: “Cursed be the one who has intercourse with his wife in her back passage.” Narrated by Abu Dawood, 2162; classed as saheeh by Shaykh al-Albaani in Saheeh al-Targheeb, 2432. 

These ahaadeeth indicate that it is haraam to have intercourse with a woman in her back passage. This is an action which goes against the fitrah (sound human nature) and incurs the wrath and anger of Allaah, and is also a cause of disease. 

Shaykh al-Islam Ibn Taymiyah (may Allaah have mercy on him) was asked about what a man who has had intercourse with his wife in her back passage should do. Has this been permitted by any of the scholars? 

He replied: 

Praise be to Allaah, the Lord of the Worlds. Intercourse in the back passage is forbidden according to the Book of Allaah and the Sunnah of His Messenger (peace and blessings of Allaah be upon him), and according to all the leaders and imams of the Muslims, including the Sahaabah, the Taabi’een and others. Allaah says in His Book (interpretation of the meaning): 

“Your wives are a tilth for you, so go to your tilth (i.e., have sexual relations with your wives in any manner as long as it is in the vagina and not in the anus) when or how you will, and send (good deeds, or ask Allaah to bestow upon you pious offspring) for your ownselves beforehand”

[al-Baqarah 2:223] 

And it is narrated in al-Saheehayn that the Jews used to say that if a man had intercourse with his wife in her vagina from behind, the child would be born with a squint. The Muslims asked the Prophet (peace and blessings of Allaah be upon him) about that, then this verse was revealed (interpretation of the meaning): 

“Your wives are a tilth for you, so go to your tilth (i.e., have sexual relations with your wives in any manner as long as it is in the vagina and not in the anus) when or how you will, and send (good deeds, or ask Allaah to bestow upon you pious offspring) for your ownselves beforehand”

[al-Baqarah 2:223] 

The word harth (translated here as tilth) refers to the place where one sews seed, and the seed for a child is planted in the vagina, not in the anus. 

Majmoo’ al-Fataawa, 32/267 

See also the answer to question no. 1103, where the ruling on having intercourse with a woman in her back passage and the bad psychological and physical effects of that are discussed. 

See also the answer to question no. 6792, which discusses the ruling along with the evidence for it. 

In the answer to question no. 49614 we have explained that a husband may be intimate with his wife whilst he is fasting, so long as he does not have intercourse or ejaculate; intercourse with one’s wife in her vagina is haraam during the day in Ramadaan, so how about if he has intercourse in the back passage and ejaculates?! 

Secondly: 

With regard to the effect on the fast you were observing at the time you did what you did: the fast is undoubtedly invalid, but you must still refrain from eating and drinking for the rest of the day. The majority of scholars stated that the day must be made up, as well as offering expiation for having intercourse in the wife’s back passage, regardless of whether he ejaculated or not. 

This ruling also applies to your wife – she must also make up that fast and offer expiation, because it seems that she was a willing participant. 

Ibn Qudaamah said: 

It makes no difference if one has intercourse in the front or back passage of a male or a female. This is the view of al-Shaafa’i…. Because he broke the Ramadaan fast by having intercourse so he must offer expiation. 

From al-Mughni, 3/27. 

In the answer to question no. 38023 it says: 

Whoever has intercourse during the day in Ramadaan deliberately and of his or her own free will, in which the two circumcised parts meet and the tip of the penis disappears in either of the two passages, has invalidated his fast, whether he ejaculates or not. He has to repent, complete that day (i.e., not eat or drink until sunset), make up that day’s fast later on and offer a severe expiation. 

The Muslim should strive to fear Allaah and avoid that which He has forbidden, especially during this month which Allaah has enjoined us to fast so that we might attain piety. Allaah says: 

“O you who believe! Observing As-Sawm (the fasting) is prescribed for you as it was prescribed for those before you, that you may become Al-Muttaqoon (the pious”

[al-Baqarah 2:183] 

And Allaah knows best.