Musnad Abu Ya'la al-Mawsili 42:130

Al-Harith ibn Surayj narrated to us, Abdullah ibn Nafi’ narrated to us, Hisham ibn Sa’d narrated to us, from Zayd ibn Aslam, from ‘Ata’ ibn Yasar, from Abu Sa’id, who said: A man had intercourse with his wife in an unconventional manner during the time of the Messenger of Allah (may Allah bless him and grant him peace). So they said: "So-and-so had intercourse with his wife in an unconventional manner." Then Allah revealed: "Your wives are a tilth for you, so come to your tilth when or how you will." (Al-Baqarah: 223)