Take a drink if you'd like. Take a swig if you'd like. Chug it if you'd like. If you want, you can chug it. If you want, you can drink it (quickly). If you'd like, you can take a swig. Drink up!

The word "chug" is seldom used when talking to another person. It is often used when describing the actions of others as "I don't believe he chugged a whole gallon of milk". The word is used to describe our own actions, especially if we regret or rue our action.