Some games have segments that require the player to press one button really fast in order to pass through. At the moment, the game that bugs me is the Legendary Starfy, but I've also run into it in Mario & Luigi: Bowser's Inside Story. (What is it with DS games and the "push a button really fast" mechanic?) For the final boss battle in Starfy, the advice is:
Once Starfy (Or Starly if in two player mode) defeats him, he will blast the moon of Bunnera at Starfy. The player must rapidly press Y to deflect it. He'll blast it again, and this time it's even harder. The best strategy is to press Y until the player is tired out, then pause the game, take a break, and do it again.
Besides taking out a contract on the developer who implemented this or hiring a neighborhood kid with fast fingers to finish the game for me, what can I do to press Y rapidly without developing debilitating RSI in my hands?