hitting him with the cold damage should be easily enough done and allowed. Yes, it's taking advantage of an ability, but... that's what you're supose to do with abilities, right? If you know about it, use it however you can to gain the advantage.
As for the sneak attack... I would have your trickster call out to the barb, "Close your eyes!" That would allow the sneak attack. However, I would make the barb roll a concentration check in order to close his eyes. He's raging. He's concentrating on killin' the baddies.
I would not allow him to ask to be hit with a cold blow, that would have to be the idea of the other party members who are still capable of thinking about these things. He should be thinking about reducing whatever he doesn't like to a bloody pulp.
Does this sound like a reasonable solution?
As for the sneak attack... I would have your trickster call out to the barb, "Close your eyes!" That would allow the sneak attack. However, I would make the barb roll a concentration check in order to close his eyes. He's raging. He's concentrating on killin' the baddies.
I would not allow him to ask to be hit with a cold blow, that would have to be the idea of the other party members who are still capable of thinking about these things. He should be thinking about reducing whatever he doesn't like to a bloody pulp.
Does this sound like a reasonable solution?