Musannaf Ibn Abi Shayba 17:1189

Waki’ narrated to us, from Hisham, from his father, from Zaynab bint Umm Salamah, from Umm Salamah, that the Prophet (peace be upon him) entered upon her and heard a *mukhannath* (effeminate man) saying to ‘Abdullah ibn Abi Umayyah, her brother: "If Allah grants the conquest of Ta’if tomorrow, I will guide you to a woman who approaches with four [folds] and departs with eight." The Prophet (peace be upon him) said: "Expel them from your houses."