Uh... does Garen's Judgement damage stack in URF?
since you can re-use it before it finishes. The second spin's damage stacks with the first's?
since you can re-use it before it finishes. The second spin's damage stacks with the first's?
You can't recast it. His spin "stacking" is done by canceling his E early, refunding enough cd to instantly recast it.
In either case it is a sustained ability, so recasting it would only refresh the duration.