Zayd bin Aslam (may Allah have mercy on him) said that a man asked the Messenger of Allah (peace and blessings be upon him): What is lawful for me from my wife when she is menstruating? He (peace and blessings be upon him) said: "Let her tie her lower garment (izar) firmly over her lower body; then the upper part is yours to do as you wish."
This is mursal.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 14081