Why Ali drinks water after running around...

Conversation with Ali as we were coming home from Outback Steakhouse for my grandpa's birthday.

A: Agua.
T: Ali, would you like some agua?
A: Yes
T: You know how to ask for it
A: Can I have some agua, please? I was running around outside with Kiki (my cousin's daughter) and if you run after you eat, then you'll throw up.
T: (I hand her the water and think she's going to say how she's so thirsty because she's been running around)
A: I need to drink agua so I can push my throw up down.