Basically you can choose when to pop your Q.
And you can E to burn her parry if you want to Q right afterwards.
I use all attack speed runes and quints along with 12/0/18 with undying grasp.
It works, try it!
So Voli top is really good against "new" Fiora
Fiora still has the capacity to shred tank-stats, sustain really well between trades, has the low mana to repeatedly Lunge in and Lunge out, and she can still Riposte Volibear's face-chomp. It's also about as likely a Fiora is going to fail Riposte as it is Voli is going to fling her in the prime spot to smack a weak point.
Really good is overselling Volibear's capacity to deal with Fiora. Volibear can certainly win that lane, but he just doesn't bring anything to the table to reliably and soundly win that lane. Fiora will also out-scale Volibear late game.
