This build is made to show how daring Ahri can be. Because if she ever gets behind with a standard build such as morello rush, you will get destroyed. With this build, your trades, your farming and your overall damage output will be insane. Mana won't be a problem thanks to the sheen and the Meditation mastery. But be sure not to waste it on stupid things such as trying to charm the minion wave or something like that.

When you reach about 100-150 Ability Power at level 9 in 10th minute, you will be able to wave clear the caster minions with just a Q (Orb casted out and back) which will deal about 300-400 while the minions will have about the same health. When you get rabadons you can waveclear it all no matter the state of the game.
How to win the lane:
Ahri is a late game champion, but when you get the cores in this build, you can already destroy your opponent. When you want to all in, make sure that you have wave cleared the caster minions. The melee minions wont reach you so screw them. At the early state, you will most likely sit under your turret. So just for about 10 minutes, farm it out and wait for the opportunity instead of being desperate for a kill

To be completely honest, Swain is the biggest threat against Ahri. Permaban him so you can get rid of him.

I've been playing with this build for months now, played 200 games as Ahri with a 65,7% winrate at ranked games. I am 100% sure everyone can use this build, cause it doesnt matter that much if you miss your skillshots, your damage output will still be completely insane in trades and all ins.

If you ever land a Q double up and you have the health advantage, then you have a big opportunity to make an all in.
Combo:
Double Q
Rush with R, empowered with W. Proc Lich Bane
Focus on your enemys walk path and hit your charm.
Use R again about 300-400 units away from your opponent.
While you just have a used R, use instantly your protobelt straight into the enemy and then proc Lich Bane again.
Then your Q is most likely up again. Use your Q and coordinate the Q's back with R