Near the end of the game, you will make it to the final tower, after flying across. There will be a large amount of suits of armor here. Trico will sometimes knock them down without eliminating them. You can then grab the suit of armor's head and pull it off. Grind here and be sure to restart the checkpoint before the final suit of armor is eliminated.
Here is a video guide with English commentary!
Here is a playlist of guides for this game!
https://www.youtube.com/playlist?list=PL-HeW6XkKdULD7WVqUHgB...