Rule Question: Blessing of The Godling

[Edward Vysenguard]

Good night everybody. Sorry for my grammar.
I've a question about this feat.

Blessing of the godling:
Benefit: Once per day you gain a number of godling tokens equal to 3 + 1/2 your godling class level. As a free action, once per round, any time a nongodling within 30 feet of you makes a d20 roll, you can choose to spend godling tokens on the d20 roll (even after the result is known). Each token grants that nongodling a +1 bonus or -1 penalty for that d20 roll only; you must announce how many godling tokens you are spending, once announced you cannot change the amount spent.

It is a free action, the question is:
1)Can i use it during enemy turn in combat for debuff them?

2)How can i use this in an efficent way in combat?

[Darksol the Painbringer]

1. Per RAW, Free Actions do not take place outside your turn unless they say they can, which means that you can't do this against an enemy attacking you on their turn. So, speech and the Grab special ability are the only known exceptions.

2. You can use this to boost a do-or-die roll (such as a Will Save or the final blow to an enemy), or you can use it to reduce the likelihood of an enemy succeeding a roll (such as a Save/Die effect for a BBEG, or a fatal Attack of Opportunity). Just be careful and watch for enemies with immunities or high saving throws against effects you may be throwing at them, as this may result in you throwing away your bonuses for the day.