Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) said: Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) was mistaken, may Allah forgive him. This clan of the Ansar were idol-worshippers living alongside this clan of the Jews, who were People of the Book, and they regarded the Jews as superior to themselves, so they followed many of their practices. It was the way of the People of the Book to approach women in only one manner, which is the most concealing for the woman, and this clan of the Ansar had adopted that from their practice. This clan of Quraysh, however, would lay women out in an unusual manner and take pleasure in them from the front, from behind and lying on their backs. When the Muhajirun came to Madinah, a man from among them married a woman of the Ansar and began to do that with her. She objected and said: "We were only approached in one manner, so do that, or else keep away from me," until the matter between them grew serious. When news of this reached the Messenger of Allah (peace and blessings be upon him), Allah, the Blessed and Exalted, revealed: "Your wives are a tilth for you, so come to your tilth however you wish." [Surah al-Baqarah: 223], that is, from the front, from behind or lying on their backs, meaning only the place where the child is born.
(b) Aban bin Salih also mentioned something similar in meaning: "It must be in the private part."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 14107