The Sunna of the Prophet regarding sexual activity during menses
Narrated Um Salama:
While I was laying with the Prophet under a single woolen sheet, I got the menses. I slipped away and put on the clothes for menses. He said, "Have you got 'Nifas' (menses)?" I replied, "Yes." He then called me and made me lie with him under the same sheet.
When ever Allah's Apostle wanted to fondle any of his wives during the periods (menses), he used to ask her to wear an Izar.AD says: an Izar is a dress worn below the waist.