I don't.
Instead, I work through things like the following, using "I" to mean "my character" for brevity:
- What am I feeling? (Rage? Pain? Joy? Fear? Hate? Love? Apathy? etc.)
- How do I make decisions? (Logical stepwise thought? "Honor before reason"? Self-interest calculation? etc.)
- What do I know? (Context, environment, opponents, allies, resources, etc.)
- What are my goals?
- How much time do I have to make a decision?
By answering these questions, I can then respond if challenged, in a reasonable and productive way, e.g.:
Player 1: (IC) "Hey, what the hell man?! We agreed to spare this guy's life!"
Me: (IC) "
You agreed to spare his life. I didn't agree to that, remember?"
P1: (OOC) "Look, that was kind of naughty word, okay? I thought we were all on board for this."
GM: "Is that a problem?"
P1: (OOC) "Well I'd at least like an explanation."
Me: (OOC) "Look, Dodec is tangled up in knots right now. This guy killed half his siblings. Normally, he's all logic and numbers, but that means he's completely blindsided by all the
rage and
pain he's feeling right now, driven by grief he's suppressed and ignored since he found out. He didn't even like most of his family very much...but he did
love them, deep down, and now he's flailing. He doesn't know about your secret agreement with the Duke...mostly because you kept it
secret. So, yeah, when he was the one to land the final blow on the man who murdered half his siblings...he's not inclined to be merciful, particularly because he
did not agree to spare the guy's life. Like he went out of his way to ignore that agreement. So, in a moment of rage, he has
no problem crisping up the guy's corpse with a
scorching ray, which is lethal."
GM: "Well...I know it's not what the rest of the group wanted, but that also sounds pretty reasonable for how a warforged might deal with grief. What do you think, P1?"
P1: (OOC) "I mean, I still don't
like it, but I see how it would be very out-of-character for Dodec to do that. By that same token though, kinda feels like Zeke is just getting what he wants even though the rest of the group disagreed."
Me: (OOC) "You know, fair enough. How about this: I've been saving up money to buy and scribe spells. Take 300 out of my purse, to pay for buying a new
revivify diamond, and we'll use one of the ones we keep with us. You still have a 3rd level slot, right?"
P1: (OOC) "Yeah. Would prefer not to spend it...but if you'll foot the bill, alright, that's a reasonable compromise. You still got the satisfaction of the kill, and I can keep my word to the Duke. Guy might not like us very much though."
Me: (OOC) "Well, if anyone can sell a tomato-based fruit salad, that'd be [Party Bard]..."
P2: (OOC) "Oh, now I have to clean up for you again? Alright
fiiiiine. Hah!"
Point being, "It's what my character would do!" is a crappy excuse to skip over doing the thinking. Actually doing the thinking, in a way that you can then communicate to someone else, obviates the need to ever use that excuse.
And if I can't commit to doing the thinking in advance? It costs me nothing to simply go with the flow and explain it as my character