Musannaf Ibn Abi Shayba 9:552

Waki’ narrated to us, from Sharik, from ‘Asim, from ‘Isa ibn Hattan, from Mujahid and Sa’id ibn Jubayr, they both said: "He discharges it." Yahya ibn al-Jazzar said: "By what thing does he make the private part lawful? By such and such, her private part."