Why are the chipmunks drinking coffee?

This is from the 2007 movie. In this scene, they fall asleep in the recording studio, so "Uncle" Ian gives them coffee to wake them up. What happens suivant is funny! :D

They are drinking coffee because they were falling asleep so Ian gave them coffee.

cause they l’amour coffee

First movie
They were falling asleep while chant "Get Punk'd" even though its known as "Get Munk'd" on the album but wasnt age appropriate for the movie just like. "Come get what toi want" which is also on the album
Ian gave it to them