Top definition
When, in cases of extreme thirst, a person using a soft-drink fountain fills the beverage container, chugs it, and then fills it again before sitting down to eat.
Person 1: Hey man, why did it take you so long to get a soda?

Person 2: I was prefilling my cup; I've been thirsty all day.
by Matt Coon August 07, 2007
Get the mug
Get a prefill mug for your guy Sarah.