Musannaf Ibn Abi Shaybah

Hazrat Umm Salamah (may Allah be pleased with her) narrates that when the Muhajirun came to Madinah, they married Ansari women. The Muhajir men would make the women sit on their knees and place their heads on the ground during intercourse, whereas the Ansar did not do so. One Ansari woman said to her husband that this matter should be asked of the Messenger of Allah (ﷺ). The woman was shy to ask, so I asked, and the Prophet recited this verse of the Holy Qur'an: { نِسَاؤُکُمْ حَرْثٌ لَکُمْ فَأْتُوا حَرْثَکُمْ أَنَّی شِئْتُمْ } "Your wives are your fields; go to your fields as you wish." Then he said that the place of entry is only one.