Sunan an-Nasa'i, Volume 1, Book 3, Hadith 374 (DarusSalam) ⓘ
It was narrated that 'Aishah said: "If one of us was menstruating, the Messenger of Allah would tell her to put on an Izar (waist wrap) then he would fondle her."
أَخْبَرَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ، قَالَ أَنْبَأَنَا جَرِيرٌ، عَنْ مَنْصُورٍ، عَنْ إِبْرَاهِيمَ، عَنِ الأَسْوَدِ، عَنْ عَائِشَةَ، قَالَتْ كَانَتْ إِحْدَانَا إِذَا حَاضَتْ أَمَرَهَا رَسُولُ اللَّهِ صلى الله عليه وسلم أَنْ تَتَّزِرَ ثُمَّ يُبَاشِرُهَا .
also referenced under: Hadith 374 (Reference) & Book 3, Hadith 26 (In-Book)