Fast TM and Charged TM

If you apply a fast TM to a unevolved Pokémon and scream what move you want it to get out loud then immediately evolve it afterwords it gets the move you screamed. If you want dragon tail on a dragonite you have to use a fast TM on a dragonair then immediately scream "dragon tail" into your phone like if you were talking to Siri, then evolve your dragonair, your dragonite will get dragon tail.

Fast is the move that builds (charges) the bar by tapping, once full you can use the charge move by tap and hold. On a pokemons page fast is the first (top) move. Charged is the second (bottom) move.

Fast is the top move, charge is the bottom move. Only use it on final evolutions of powerful Mon who get crappy moves.
You should experiment with battle. If you wonder, "why is my Tyranitar terrible?" Then use a charge TM to get rid of Fireblast. Or if you think, "My Machamp blows", the use a fast TM to switch Bullet Punch to Counter.

I hope this is not a troll...
But i will explain anyway.

Fast TM, changes the fast move
Charge TM, changes the charge move
(whoda thought?)

When you click one, it takes you to your pokemon and you select one that you wish to change the corresponding move on (depending on what type of TM you have selected to use)

You get a little box telling you what you are to roll anyway so you should know exactly whats going on and not change something by mistake.