Abdullah bin Abbas reported,

Ibn Umar, may Allah forgive him, was mistaken. What actually happened was that this tribe of the Ansar, who were idolaters, lived alongside this tribe of the Jews, who were people of the Book. The Ansar regarded the Jews as having superior knowledge, so they would imitate them in many of their practices.Among the customs of the people of the Book was that they would only approach women from one side, considering this the most modest position for a woman. So this tribe of the Ansar had adopted this practice from them. The Quraysh, on the other hand, would lay women open in shocking ways, taking pleasure with them from the front, from behind, and while reclining.When the Muhajirun arrived in Medina, one of them married a woman from the Ansar. He went to be intimate with her in his accustomed manner, but she refused and said, "We are only approached from one side, so do that, or else stay away from me," until their dispute became serious.News of this reached the Messenger of Allah ﷺ, so Allah revealed, "Your women are a tilth for you, so come to your tilth as you wish" [Baqarah 2:223], meaning from the front, from behind, or while reclining, referring by this to the place of childbearing.

عن ابن عباس قال

إن ابن عمر- والله يغفر له- أوهم، إنما كان هذا الحيي من الأنصار- وهم أهل وثن- مع هذا الحيي من يهود- وهم أهل الكتاب- وكانوا يرون لهم فضلا عليهم في العلم، فكانوا يقتدون بكثير من فعلهم. وكان من أمر أهل الكتاب أن لا يأتوا النساء إلا على حرف، وذلك أستر ما تكون للمرأة. فكان هذا الحيي من الأنصار قد أخذوا بذلك من فعلهم، وكان هذا الحيي من قريش يشرحون النساء شرحا منكرا، ويتلذذون منهن مقبلات ومدبرات ومستلقيات. فلما قدم المهاجرون المدينة. تزوج رجل منهم امرأة من الأنصار، فذهب يصنع بها ذلك، فأنكرته عليهم وقالت: إنما كنا نؤتى على حرف فاصنع ذلك، وإلا فاجتنبني حتى شرى أمرهما. فبلغ ذلك رسول الله ﷺ فأنزل الله عز وجل: {نساؤكم حرث لكم فأتوا حرثكم أنى شئتم} أي مقبلات، ومدبرات، ومستلقيات، يعني بذلك موضع الولد.