It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the verse "Your wives are a tilth for you" was revealed to the Messenger of Allah (peace and blessings be upon him) only to give a concession for having intercourse by the rear way.
Imam al-Tabarani (may Allah have mercy on him) said: "No one narrated this hadith from Ubaydullah bin Umar except Yahya bin Sa'id, and Muhammad bin Yahya is alone in narrating it."