A bad head cold, the kind that makes your nose drip constantly. From the slurping sounds made by sniffling, and the sounds of noodles being slurped by one with such a cold.
I have a real slurper today. And I know who gave it to me. Someone was coughing right in my faceon the train three days ago!
That guy in the cubicle next to me is a total can slurper, I can hear him drinking that soda over my headphones. I could even hear him suckin up beers at the company picnic over the DJ.