Sunan an-Nasa'i 376
سنن النسائي#376Da'ifIt was narrated that Maimunah said:"The Messenger of Allah (ﷺ) would fondle one of his wives when she was menstruating, if she wore and Izar (waist wrap) that reached halfway down her thighs or to her knees
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiDaif
In-book reference: 3:28