ENOfficial
'Abdul-Muhaimin bin 'Abbas bin Sahl bin Sa'd As-Sa'di narraed from his father, from his grandfather, that: The Messenger of Allah (ﷺ) said: "Rinse your mouths after drinking milk, for it has some greasiness in it."
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا أَبُو مُصْعَبٍ، حَدَّثَنَا عَبْدُ الْمُهَيْمِنِ بْنُ عَبَّاسِ بْنِ سَهْلِ بْنِ سَعْدٍ السَّاعِدِيُّ، عَنْ أَبِيهِ، عَنْ جَدِّهِ، أَنَّ رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ قَالَ " مَضْمِضُوا مِنَ اللَّبَنِ فَإِنَّ لَهُ دَسَمًا " .
sunnah.com