It is in the barb handbook....First, rage xD
My barb died once in similar circumstances. Surrounded by harpies, already pretty hurt, I used Reckless for (well I can't even remember my reasoning, but it was bad reasoning, even without the benefit of hindsight). Harpies attacked me back and the advantage they got turn what would've been like 2 hits into 4 hits and 2 crits. Died immediately.