When you overeat and burp, you get a chunk of puke in your throat, and you swallow it again
Girl 1: You look green, what's wrong?
Girl 2: I just regurged some of that pizza from dinner.
the word regurge was made up by a group of young men on a mission to get pissed late at night, one night they ran out of beer and couldn't get anymore til the next day, it was then that "Regurge" was spat out of the young mans mouths
since then, regurge can mean anything that's bad, like not gettin any beer whaen ya want it!!