Musannaf Ibn Abi Shayba 9:1403

Yahya ibn Adam narrated to us, from Hammad ibn Salamah, from Yahya ibn Sa’id, from Sa’id ibn al-Musayyib, regarding a man who enters into a *kitabah* (contract of manumission) with his wife and stipulates in the *kitabah* that he may have intercourse with her: He said: "There is no harm in it. He has his condition, and he has the right to have intercourse with her."