Mishkat al-Masabih #422
Purification
The Arabic includes the chain of narration (sanad) and the collector's commentary; the English translation shows the Prophet's words only.
وَعَنْ أَنَسٍ قَالَ: كَانَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يطوف على نِسَائِهِ وَبِغسْلِ وَاحِد. رَوَاهُ مُسلم
Anas said that the Prophet used to have intercourse with his wives, with only a single washing.
Muslim transmitted it.
About Mishkat al-Masabih
This hadith is #422 from Mishkat al-Masabih, in the Book of Purification.