Well technically Flaire to there only to reward players for doing something besides "I hit it with my sword...again."  The game wants to reward them for dynamic play and approaching problems from different angles.  So use an underused skill in an interesting way?  Flaire!  Rinse and repeat?  No Flaire.

What you want to be doing is throwing Hero Points at your players.  When your players do something that just blows you away because its inventive or dynamic?  Hero Point!  Which they can spend to add extra dice to an Approach down the road.

So no, don't go adding dice to their next roll.  Give them hero points and let THEM do that.  :)

You're not doing anything wrong.

I actually had a similar problem with one of my players the first time I ran this game for my usual group.  He usually adds quite a bit of flavor to his actions in other RPGs, and didn't quite grasp that in this system said "flavor text" needs to be applied before the dice are rolled for the approach, so he was unintentionally causing things to drag as he gave flowerly descriptions for each raise as he spent them.  Resolved it just by saying that if he's looking for bonuses, he needs to give the flowerly descriptions when he's declaring his Hero's approach, not after the dice were rolled.

Easiest solution is just simply speak to your players about it, saying that given how the system pretty much allows them to succeed the moment they choose to roll the dice, that they need to give you the showy descriptions of what they're doing as they're telling you the approach.  And as they do so, be sure to award them with one or more bonus dice on top of the "first time skill is used this sequence."

It's a bit of a cognitive switch from other RPGs, where you tend to wait until after you've seen the result to narrate what precisely your character did, but again just speaking to your players about it should resolve the issue.

I agree with tossing them Hero Points for things after the dice are rolled. I also see no harm in rewarding a player with flair on a second round roll in combat should a fight last that long. (After all if he has been on a roll doing awesome things, that next roll should be amazing). And there is no reason to exclude either option. You can switch it up during play so long as you apply it fairly to all players.

If your players play their activity in an awasome way, give them the flair bonus die, even if that happens before their descriptions. You can just assume they will narrate it nicely:). Or assume that each character have +1 for each trait :). 

Personally, I woudn't use Hero points for rewarding for good descriptions of their actions. Thats what flair dice is for. I want players to earn HP by failing risks, using their Arcana or Quirks. That really adds to the drama. Good descriptions makes amazing atmosphere, but doesn't guarantee to push story forward.

@LechGórski, thanks for joining these forums and offering some good ideas. Welcome on board. Today is also Pi Day and the anniversary of the successful funding of the 7th Sea Kickstarter last year.