Ash'th bin 'Abdul Malik أشعث بن عبد الملك الحمراني · The Book of Purification

"When (a man) sits between the four parts of his wife's body and exerts himself, then Ghusl becomes obligatory." Abu 'Abdur-Rahman said: "This is a mistake what is correct is; 'Ash'ath from Al-Hasan, from Abu Hurairah.' An-Nadr bin Shumail, and others, reported the Hadith from Shu'bah just as Khalid reported it."