Rolling Combo! Achievement
Activate the Rolling Combo with Sonic and Tails.
The earliest this can be done is in "Sylvania Castle Zone" Act 3.
Pressing activates different combos depending on what you are doing. Jump in the air and it will cause a Sonic 3 styled action where Tails lifts Sonic in the air for you to fly around, do it underwater and Tails acts like a propeller for you.
For this achievement however you need to be in standing position on the ground. Use and the rolling combo will activate.