The “chug” in the Rattlin’ Chug Bug’s name comes from the primary action that’s produced by this bait’s mouth. When the lure is twitched along the surface, the cupped mouth makes a chugging or gurgling sound as the bait pushes a small wave of water forward. The Rattlin’ Chug Bug was one of the earliest baits to produce this kind of action and therefore became one of the baits synonymous with this whole genre of lure.
You can walk a Rattlin’ Chug Bug as well, twitching it a little slower so the bait kicks to one side and then the other. When you fish it this way, the mouth doesn’t dig in as much but there’s still a noticeable chug at the front of the bait. It’s not as pronounced as when you’re simply chugging the bait along in a straight line, but the subtler gurgling action is still there and that sets this bait apart form other topwater lures you can walk like a Spook or a Sammy.