Musnad Ahmad 1153:1257

Yahya ibn Zakariyya narrated to us, he said: My father narrated to me, from Abu Ishaq, from Abu Maysarah, from Aisha, the Mother of the Believers, she said: "When I would menstruate, I would fasten an izar (lower garment) upon myself, then I would enter with the Prophet, peace and blessings of Allah be upon him, into his garment (shiar). But he was the most capable among you of controlling his desire."