What can you do with tails following in ultimate flash sonic?

It seems you're asking about the game "Ultimate Flash Sonic." However, there isn't a game with that exact name. It's possible you're thinking of a specific Sonic the Hedgehog fan game, or perhaps you've misremembered the name.

To help me understand better, could you please clarify the following:

* What game are you specifically referring to? Please provide the full title if possible.

* What do you mean by "tails following?" Are you asking about a gameplay mechanic where Tails follows Sonic? Or are you asking about a specific feature or level?

Once I have this information, I can provide you with a more accurate answer.