Musannaf Ibn Abi Shayba 1:690

Hushaym narrated to us, from al-‘Awwam, from Ibrahim al-Taymi, that he used to say regarding the person in a state of major ritual impurity (junub): He begins by washing his right hand, then he pours with it onto his left hand and washes his private part and whatever (impurity) has touched it. Then he rubs his hand against the wall, then he performs ablution (wudu).