Sahih Muslim , Book 3, Hadith 696 (USC-MSA) ⓘ
Ibn Abbas reported: The Apostle took milk and then called for water and rinsed (his mouth) and said: It contains greasiness.
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا لَيْثٌ، عَنْ عُقَيْلٍ، عَنِ الزُّهْرِيِّ، عَنْ عُبَيْدِ اللَّهِ بْنِ عَبْدِ اللَّهِ، عَنِ ابْنِ عَبَّاسٍ، أَنَّ النَّبِيَّ صلى الله عليه وسلم شَرِبَ لَبَنًا ثُمَّ دَعَا بِمَاءٍ فَتَمَضْمَضَ وَقَالَ " إِنَّ لَهُ دَسَمًا " .
also referenced under: Book 3, Hadith 119 (In-Book) & Hadith 358 (Reference)