The Nurturer tells GPs, "Drink some milk. Drink some water..." As always with new vocabulary, start with two, and add one new one at a time. At some point, you can add the action "pour". And you can even try adding, "Pour me some juice. Pour the girl's big brother some juice." But be sure to mix pouring with drinking.
Materials to gather
If you don't want to actually pour milk, water, juice, soda, tea, into glasses and cups, you can set containers of each liquid on your learning table, and set a glass or cup next to each container. Needless to say, if the language you are learning is spoken by people whose material culture is radically different (and you and your Nurturer live in that cultural setting), you will always collect the common everyday objects (e.g., what they drink out of, what they drink) rather than the ones suggested here.