I seemed to always be the "backup guy" for one friend of mine who's gotten into more fights than anyone I've ever known combined x3.
But here's two accounts: First, 4th Grade, my friend is being picked on by the two biggest kids in our grade (twins) so he stomp kicks one in the gut and the other tackles him. I'm sitting on a tire (in the playground) when it happens and he says "Don't let the other get me" so I stand on the tire and call the kid who was stomped (who was standing and really angry) a buttface. He runs at me and I just jump off the tire and land both feet first on his right shoulder. We go down, I land on his back and actually wrap one are around his neck and the other under his armpit and sqeeze for dear life and he tried to shake me off. Yup, I invented the back-mount in 4th grade (My friend GnPed the other until he cried and a teach heard us)
Second account: Freshman year high school. This is why I'll never go to a football game. Three football jocks make fun of my friend for having a large nose and not even being a jew. So he punches one in the face sending him over the bench stunned, and pushes the other against a locker. I had been taking krotty but I literally forgot all of it and instinctively shouldered one into a locker and using what my dad showed me of what he learned in the Thai Army so many years ago I grabbed his shoulder and elbow and began to knee, I didn't even care where I hit him, just a lot.
What really sucks is while I was owning this guy my friend had been ganged up on and was being kicked in the gut on the ground by one as the other got me from behind and tackled me punching me in the face. So basically we lost, but I went from being nerd-y kid who hung around with the punk to being psycho-who's-dad-can-teach-you-to-kick-ass and my "punk" friend broke one of their noses and gave both black eyes and cuts on their foreheads.
Now here's an account of my dad's (because I love this story): My dad just moved to America rom Thailand and is going to Boston College and dating my mom. He's on the soccer and badmitten team. A linebacker doesn't like inter-racial mingling and challenges my dad (who apparently got in fights all the time in Thai Private School, go figure) so the linebacker "charged me and I kicked him a couple times right on the side of the knee, I think I broke it because I heard a crack and he went down hard and was out of football for the year"< His words.
A metal-head bloke in my year tried to tackle me after a verbal dissagreement, from the upper body, if you know what i mean, and i tripped him, he tried to get a hold of my neck so i sat on top and belted him until he cried. That was about 2 years ago (i think i was in year 10).
Another time in year 9 a kid in my year was choking a short freind of mine, who was a year below. He was just being a dick, but the kids face was turning reddy purple and he wasnt sropping, i walked up and smacked his ear, grabbed his head and gave him a nice headbutt that pretty much sent him reeling.
Of course i got belted up plenty on the footy feild but i usually just let the other guy take the suspension that came with it and got to play again next weekend..