We used to practice withdrawal while the Quran was being revealed.
حدثنا قتيبة وابن أبي عمر قالا حدثنا سفيان بن عيينة عن عمرو بن دينار عن عطاء
كنا نعزل والقرآن ينزل
Agreed upon. Bukhari narrated it in "Nikah," chapter on withdrawal (azl), no. 5208, and Muslim, no. 1440, from the hadith of Sufyan bin Uyayna through this same chain.