[hijinks]

You have a horrible PM if that person is tossing extra work at you. Your PM should be tracking your time to your goals and know if you are on track or behind. If you are ahead they should be able to add work if needed.

Anyone else that asks you to do something should go through the PM. Its up to your PM to decide if that work should be done before your sprint work is done.

So tell people to talk to your PM. If that person has no idea how to be a PM then its time to talk to your boss to find a real one