The most similar one is the Bongo Cat thing, from what I can recall/search up.
No, this isn’t just banging on a flat surface, it’s a specific pattern. It does like ‘dun dun dun-dun-dun dun-dun-dun-dun dun-dun’. I’ve heard it throughout my life and from a bunch of different sources, so it’s pretty commonly known, but I still have no idea what it’s called.
Context: On her 3D karaoke streams, Elizabeth is only willing to sing particularly spicy songs if she's using a character model that wasn't specifically made for her. I don't know where she got the one shown here, but what I do know is it's a free-to-use model that she chose because it only kinda looks like her usual avatar.
Added check translation because I'm not 100% sure my interpretation of the way Hachiroku is being addressed by Masamune is accurate. Once more info about these characters is released, I can use the added context to check the translation again.