Sunan an-Nasa'i, Volume 1, Book 3, Hadith 378 (DarusSalam) ⓘ

It was narrated from Al-Miqdam bin Shuraih, from his father, that 'Aishah said: "The Messenger of Allah would put his mouth on the place from which I had drunk, and he would drink from my leftovers when I was menstruating."

أَخْبَرَنِي أَيُّوبُ بْنُ مُحَمَّدٍ الْوَزَّانُ، قَالَ حَدَّثَنَا عَبْدُ اللَّهِ بْنُ جَعْفَرٍ، قَالَ حَدَّثَنَا عُبَيْدُ اللَّهِ بْنُ عَمْرٍو، عَنِ الأَعْمَشِ، عَنِ الْمِقْدَامِ بْنِ شُرَيْحٍ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، قَالَتْ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَضَعُ فَاهُ عَلَى الْمَوْضِعِ الَّذِي أَشْرَبُ مِنْهُ وَيَشْرَبُ مِنْ فَضْلِ شَرَابِي وَأَنَا حَائِضٌ ‏.‏