Apparently, this is is the fastest way to drink bottled water. Redditor t0mbstone also adds:
"Supposedly, the trick is to relax your throat, tensing whatever muscles block off the entry to your lungs, and "inhale" with your stomach. This is similar to the technique used by people who can burp on command by pulling air into their stomach, then compressing their stomach to release the air in the form of a burp."