When I'm stable, my thinking is far "quieter" and relaxed, so to speak. Nevertheless, I still communicate a lot to myself, and if available, to others. What's going on now is a lot of pushing to complete projects. Go, go, go! Also, bouts of frustration and impatience. I don't currently have anxiety (or at least not typical types).

I definitely experience racing thoughts during hypomania, mania, and mixed states. The "flavor" affects the topics that go on. Elated, extra extra frustrated, depressed mixed in, anxious? It varies. I, too can have a lot of repetative stuff going on then. Not just songs/sounds, but phrases. Some are self cheering on. Others can be declarations of joy. When mixed, fantasies of violence even though I'm not generally a violent person. When I become so, it's only directed at either myself or maybe a wall/inanimate object, even if directed towards others in my mind. Daydreaming of various sorts increases. I can start to feel distant from myself.

When very manic, my thoughts race so much that it's like a chaos of everything, with multiple stuff happening in there rapidly and simultaneously. Sometimes to the point of a type of explosion.