new super mario bros ds world 5-3 secret exit

The Secret Goal leading to this cannon is in World 4-Fortress. On the other side you'll find the red secret exit flag. It's a tough maneuver - try to vault off of the corner of the pink square when its highest position. When the pink square comes to a halt by the exit flag, run and leap left, then use the Propeller Suit to buzz up and into the vertical red pipe at the very top of the screen. You'll need to keep the Propeller Suit all the way until the very end of this level to find the secret exit. The Secret Goal leading to this cannon is in World 2-6.

On the other side you'll find the red flag signifying the hidden exit. Run to the right at the very top of the screen, past Star Coin #3, into a hidden pipe. You'll can get up there with the help of Yoshi or a Propeller Cap. The hidden exit is actually above this secret area. Just before Star Coin #3 is a secret area you can access high above the ground which is on revealed when you stumble into it - there are several coins in the hidden area. The Secret Goal leading to this cannon is in World 1-3.

New super mario bros ds world 5-3 secret exit