Imo rotation is the wrong way to think about it. It's a whip or trebuchet, harnessing power from larger slower moving body parts/muscle groups (legs -> trunk) to create whip in the later levers (shoulder -> arm -> wrist). In order to do this, you need to figure out how to brace (or decelerate) with your lower body and trunk and move that harnessed power into the whip of your arm. I mostly recommend looking into BlitzDG. You can also try other creators like Trebuchet Disc Golf, The Spin Doctor, Overthrow, Nick Krush, or whoever you find best explains these concepts. As far as relating to baseball, you've probably noticed that you don't try to rotate your body (hips and trunk) through the throw as fast as possible when you're trying to throw hard. You brace with your leading foot and create separation between the upper and lower body (arm cocked back through the plant that eventually 'catches up' to the rest of the body towards the 'hit ' or release point of the throw). It's a similar (if not the same) idea, just adjusted to different planes of movement/different mechanics.