Sahih Al Bukhari (292)

سأل زيد بن خالد الجهني عثمان فقال: أرأيت إذا جامع الرجل امرأته فلم يمن؟ قال عثمان: يتوضأ كما يتوضأ للصلاة، ويغسل ذكره. قالعثمان: سمعته من رسول الله صلى الله عليه وسلم. فسألت عن ذلك علي بن أبي طالب، والزبير بن العوام، وطلحة بن عبيد الله، وأبي بن كعب، رضي الله عنهم، فأمروه بذلك.

Zayd ibn Khalid Al Juhany (may Allah be pleased with him) narrated: I asked `Uthman ibn `Affan about a man who engaged in the sexual intercourse with his wife but did not discharge. `Uthman replied: "He should perform ablution like that for the prayer after washing his private parts." `Uthman added: "I heard that from Allah’s Messenger (peace be upon him)." I asked Ali ibn Abu Talib, Az-Zubayr ibn Al `Awwam, Talha ibn `Ubaydullah and Ubay ibn Ka`b and all gave the same reply.