【ずるずる・zuru zuru】slurping sound
ずるずる is the Japanese onomatopoeia for a slurping sound.
If you’ve been to a ramen shop in Japan, you may have questioned all the ずるずる slurping sounds. In Japan, making slurping sounds when eating noodles are considered normal. Some will say that you’re supposed to make slurping sounds and it is even considered the proper way.