The manual says it's a twist, I believe. I glanced through mine earlier, and that's what it said.
Edit: On a different note, I've now decided that Nintendo should name Yellow Toad and Blue Toad.
Taking a page from the modern Princess Toadstool, who is now Princess Peach, I believe, as natives to the Mushroom Kingdom, they, too, should be named after fruit.
Yellow Toad's name is Mango. Blue Toad's name is Plum. The End.
Now, if only I could get a hold of Nintendo and Miyamoto to tell them this.