Hadith 8:739
Abu Bakr narrated to us, he said: Sahl ibn Yusuf narrated to us, from ‘Amr, from al-Hasan, regarding the one who has intercourse with his wife while he is in the state of Ihram for both of them: He said, "Upon him are two camels [as expiation]."
حدثنا أبو بكر قال حدثنا سهل بن يوسف عن عمرو عن الحسن في الذي يقع بأهله وقد أهل بهما قال عليه بدنتان