Mustadrak al-Hakim — Hadith 3142

It is narrated from Mujahid; he said: I presented the entire Qur'an to Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) three times. I would stop him at every verse and ask him about its revelation and its background. When I reached this verse: "Your women are a tilth for you, so come to your tilth however you wish" [Surah al-Baqarah: 223], he explained: This clan of the Muhajirun used to lay their women (during intercourse) in various positions, whether from the front or from behind. When they came to Madinah, they married women of the Ansar and wanted to do with them as they used to do with the Muhajir women. The Ansari women disliked this and complained about it to the Messenger of Allah (peace and blessings be upon him). Then Allah, the Mighty and Majestic, sent down this verse: "Your women are a tilth for you, so come to your tilth however you wish." Its meaning is: whether from the front or from behind, provided that it is in the place of childbirth (the private part). Ibn Abbas (may Allah be pleased with them both) clarified that it means coming from behind, but into the private part itself.
This hadith is sahih (authentic) on the condition of Muslim, and the two Shaykhs (Bukhari and Muslim) did not record it.