I would remove the drink, and say no more if you are going to be silly. If she throws a tantrum just stay with her till she calms down and then tell her that she needs to drink her drink properly. Give a 10 min break before reoffering the drink. And before giving it to her remind her that she needs to drink it properly or mummy will take it away. The first time she will think the world is ending But she'll get the idea.