Tsubu-tsubu: A bubbly, rounded texture, like bubble tea or tapioca pearls. Smooth rolling feel.
Sube-sube: A smooth, rounded texture, but not segmented like tsubu-tsubu. A smooth-textured, melting feel.
Toge-toge: A spiky texture. ‘Toge’ means spike. The feel/texture of spikiness/poking.
Zara-zara: The sound and feel of rough but fine friction, like sandpaper. Looks like it’s designed to have a finely rough mouthfeel.
Goro-goro: The sound/feel of rough rolling, like an object that isn’t precisely round rolling down a hill or some stairs. Think of the sound a rough boulder would make rolling down a mountain instead of a large, smooth ball. Tumbling. The cubes are designed to break apart and tumble around in your mouth.
Fuwa-fuwa: Fluffy, light and airy. A poofy dog’s fur or an 80’s Tina Turner hairdo would also be described as ‘fuwa-fuwa’.
Poki-poki: Poki-poki doesn’t refer to the fine frame or structure particularly; more the feel/implied sound of it breaking apart. This is why the candy Pocky (Pokki) is named what it is, for that ‘poki!’ snap when you bite it. The candy’s framelike structure is in order to experience that ‘poki!’ feeling.
Zaku-zaku: Crispy-crunchy. The sound/feel of snacky, airy crunching. For example, a walnut wouldn’t necessarily be ‘zaku-zaku’ even if it is crunchy, but a matzo cracker or saltine or something like that would be.

Sorry if this sounds pretentious. Japanese onomatopoeia is just a particular interest of mine. 🙂