As the name suggests. Its a chill stream, but everytime Neuro talks about her cat, the neko mode gets triggered for one minute. The effect stacks.
Alternative idea: Cat mode is triggered from the start and set to stay for the whole duration. Neuro is told prior to going live that she is a cat today and should talk about cat related topics. Could be supplemented with little additions like a cat collar with a bell, or perhaps a background that looks like a cat room with a scratching post and food bowl.