Sunan an-Nasa'i, Book 1, Hadith 287 (In-Book) ⓘ
It was narrated that 'Aishah said: "The Messenger of Allah would tell one of us, if she was menstruating, to tie her Izar (waist wrap) tightly then he would fondle her."
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا أَبُو الأَحْوَصِ، عَنْ أَبِي إِسْحَاقَ، عَنْ عَمْرِو بْنِ شُرَحْبِيلَ، عَنْ عَائِشَةَ، قَالَتْ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَأْمُرُ إِحْدَانَا إِذَا كَانَتْ حَائِضًا أَنْ تَشُدَّ إِزَارَهَا ثُمَّ يُبَاشِرُهَا .
also referenced under: Volume 1, Book 1, Hadith 286 (DarusSalam)