Muwatta Malik #127
Purity
Yahya related to me from Malik from Nafi that Ubaydullah ibn
Abdullah ibn Umar sent a question to A'isha asking her, "May a man
fondle his wife when she is menstruating?" She replied, "Let her wrap
her waist-wrapper around her lower part and then he may fondle her if
he wishes."
About Muwatta Malik
This hadith is #127 from Muwatta Malik, in the Book of Purity. Muwatta Malik contains 1,985 hadiths across 61 books.