From Sonic Retro
The Tail Swipe or Tails Attack is one of Tails' signature moves. Debuting in Sonic Adventure, it has stayed with Tails for most of his subsequent 3D outings, as well as migrating back into 2D for all three Sonic Advance titles.
For this move Tails performs a 360° spin, lashing out with his twin tails to smash any foes in front of him. Rarely as useful (or safe) as a regular spin attack, the move is not a particularly well-used one apart from in Sonic Adventure, where it can be powered up significantly by acquisition of the Rhythm Badge, an upgrade in Mystic Ruins. The Rhythm Badge allows Rapid Tails Attack to be used; a continuous Tail Swipe switching Tails' 360° spin for a sustained twirling motion. Indeed, Tails seems at his most acrobatic when using the move, pirouetting on his feet and hands as he sweeps across the ground like a whirling foxy dervish.
This upgraded move is excellent for ploughing through whole rooms of E-Series robots and just generally going fast. How Tails keeps his stomach despite spinning at several hundred rpm is anyone's guess. In Sonic Advance 2, Tails is able to pull off a similar moving Tail Swipe while in Boost Mode; here it is called the "Super Tail Swipe".