Sunan an-Nasai Book 1, Hadith 237

أَخْبَرَنَا سُوَيْدُ بْنُ نَصْرٍ، قَالَ حَدَّثَنَا عَبْدُ اللَّهِ، عَنْ سَعِيدِ بْنِ يَزِيدَ، قَالَ سَمِعْتُ عَبْدَ الرَّحْمَنِ بْنَ هُرْمُزَ الأَعْرَجَ، يَقُولُ حَدَّثَنِي نَاعِمٌ، مَوْلَى أُمِّ سَلَمَةَ رضى الله عنها أَنَّ أُمَّ سَلَمَةَ سُئِلَتْ أَتَغْتَسِلُ الْمَرْأَةُ مَعَ الرَّجُلِ قَالَتْ نَعَمْ إِذَا كَانَتْ كَيِّسَةً رَأَيْتُنِي وَرَسُولَ اللَّهِ صلى الله عليه وسلم نَغْتَسِلُ مِنْ مِرْكَنٍ وَاحِدٍ نُفِيضُ عَلَى أَيْدِينَا حَتَّى نُنْقِيَهُمَا ثُمَّ نُفِيضَ عَلَيْهَا الْمَاءَ ‏.‏ قَالَ الأَعْرَجُ لاَ تَذْكُرُ فَرْجًا وَلاَ تَبَالَهُ ‏.‏

Abdur-Rahman bin Hurmuz Al-A'raj said:"Na'im the freed slave of Umm Salamah narrated to me that Umm Salamah was asked: 'Can a woman perform Ghusl with a man?' She said: 'Yes, if she is well-mannered.[1] I remember the Messenger of Allah (ﷺ) and I performing Ghusl from a single wash tub. We would pour water on our hands until they were clean then pour water over them.'" Al-A'raj said: "Not mentioning the private area not paying attention to it." [1] Kaiysah:" Well-mannered when using the water with the man" (An-Nihayah) And the comments by Al-A'raj after the narration refer to its meaning