Ibn Abbas reported that the Prophet ﷺ drank some milk, then called for water and rinsed his mouth, saying, "It has greasiness to it."
أخبرنا قتيبة، قال حدثنا الليث، عن عقيل، عن الزهري، عن عبيد الله بن عبد الله،
أن النبي ﷺ شرب لبنا ثم دعا بماء فتمضمض ثم قال إن له دسما.
Bukhari narrated it in the Book of Wudu, Chapter: Does One Rinse the Mouth Because of Milk, Hadith no. 211, and Muslim narrated it in the Book of Menstruation, Chapter on the Abrogation of Wudu Because of What the Fire Has Touched, Hadith no. 358, from Qutayba bin Saeed with this wording, and it is also in Al-Kubra, Hadith no. 192.