From the Super Mario Wiki
The Helicopter Spin (also called the Ponytail Spin, alternatively parsed as pony tail spin) is an ability performed by Dixie Kong in the Donkey Kong Country and Donkey Kong Land series. She first performs this ability in Donkey Kong Country 2: Diddy's Kong Quest and Donkey Kong Land 2. She also uses her Helicopter Spin in Donkey Kong Country 3: Dixie Kong's Double Trouble!, Donkey Kong Land III, and Donkey Kong Country: Tropical Freeze.
Since Dixie cannot cartwheel like Diddy or roll like Kiddy, Dixie rather uses her ponytail to spin into enemies. She primarily uses the Helicopter Spin while in midair, allowing her to safely move across gaps and other stage hazards; this move effectively slows her descent. Dixie performs the move by whirling her ponytail around in a circular motion, hence the ability name. In Donkey Kong Country 2 and Donkey Kong Country 3, if Dixie is accompanied by Diddy or Kiddy respectively, her partner Kong rolls in the air while she uses Helicopter Spin.
In few cases, Dixie's Helicopter Spin is required for crossing certain large gaps that the other Kongs cannot do so alone. For instance, in Donkey Kong Country 3 at the start of Stampede Sprint, there is a large divide that can only be crossed via her Helicopter Spin. The ability is sometimes used to more easily reach a Bonus Barrel: for example in Donkey Kong Country 2, during the second level Mainbrace Mayhem, while Diddy can perform a cartwheel to reach the Bonus Barrel, Dixie's Helicopter Spin lowers the risk of Diddy missing a jump and losing a life.
In Donkey Kong Country: Tropical Freeze, the Helicopter Spin allows Dixie to gain a small boost in altitude, along with Donkey Kong.
In the original Super Nintendo games, the player can press to have Dixie perform a Helicopter Spin. In the Donkey Kong Land games, this is accomplished by pressing , and the Game Boy Advance versions also requires .
In Donkey Kong 64, Tiny Kong uses a similar move for both attacking and gliding, known as the Pony Tail Twirl. In the Super Smash Bros. series, Donkey Kong uses a similar move as his recovery, Spinning Kong, where he spins to briefly propel himself into the air.