How do you get masks for the hero in Patapon 2?

Answer 1

You have to enter the Patagate. After you finish the mission, you have do well on the Don Chaka party song. If you did well then you'll receive a mask.

Some footnotes:

1) Different bosses will provide you with different masks, read the description on the egg for a hint to the mask's boost.

2) If you don't know anyone with another PSP and Patapon 2, select 'Play Alone' from the Herogate Screen. You can still acquire masks. (I did)

Hope it helps =]