Why is the cartoon kid drinking and blinking?

The cartoon kid might be drinking water because they were active and needed to hydrate. The blinking could be a way to add some charm or cuteness to the scene. It's all part of the animation's way of making the character more engaging.

Maybe the kid is thirsty and needs a drink to quench it.

The cartoon kid might be drinking water because it's a healthy habit. Maybe they were told to drink water regularly or they just feel like it at that moment.

The cartoon kid could be drinking milk to get essential nutrients for growth and development. Or it might be part of a daily routine.

The kid vomiting after drinking in the cartoon might be due to an allergic reaction to an ingredient in the drink. Or, it could be a part of the story to show some sort of consequence or mistake. Maybe they drank something they weren't supposed to.

Maybe she's trying to get attention or show some kind of emotion.

No, it's not appropriate. Kids should not be depicted consuming alcohol as it sends the wrong message and can have negative impacts on young viewers.

Maybe the deer is curious or fascinated by the strange blinking lights. It could be a plot device to draw the viewer in.

The cartoon guy might be drinking because he's at a party and wants to have fun. Or it could be that it's a hot day and he needs to cool off with a drink.

Maybe the baby is thirsty and needs some liquid to quench its thirst.