I'm thinking Skill Swapping a Pokemon with Soundproof, switching out, and then bringing out another Pokemon with Soundproof. Are there any other things you could do?
Try using taunt on the politoed before it uses perish song with a Pokemon that has prankster, like whismicott, also, when the taunt runs out, use it can because you have priority. Hopefully this answers your question. Hope I helped!
I don't really think you should make an effort to counter it, just switch out. If you really want a switch in you could use soundproof I guess but really it's not worth it.
