I got bullied several times in my life. Or rather harrassed, nothing too vile, I suppose.
One guy surrounded by his gang would regularly bother me during lessons by throwing wads of paper at me from behind.
Then one day he snipped my ear, which was more startling than painful. I rather calmly turned around and in the same fluid motion gave him a loud open handed smack to his face, which caught him rather off guard.
He grabbed my hand immediately and looked at me with a raging face, fully prepared to floor me if I followed through with another one. I didn't. I merely looked at him with a kinda bored expression, my caught arm limp in his grip. After a few seconds he forcefully gave me my hand back, I turned around heart beating. Of course, everyone in class saw this, teacher included, and all was silent for a few seconds more. Then the teacher resumed class like nothing happened.
He never bothered me again and strangely no one ever mentioned this episode to me or with me hearing about it. Also, most of the bullying from others faded away thereafter, too. I assume it was because I lost the easy-target label. But honestly I don't think that I was that high a priority in their lives either, so I got away easy. I was about 16 to 18 when that happened.
Another episode after this involved a classic bully - big, stupid, loud nasty laugh, racists, more fat than muscle but height and mass to back up his antics. He had his social cirlce but i didn't get the impression that they feared him because of his power or all that cliche nonsense. He simply had his friends, end of story. No crappy Stephen King novel here, move on.
This guy had his sights on me for all the time since he came to my school. Could be because he was a big racists german and me a smaller asian, could be because I was just smaller and under scrutiny of the whole gang anyway (he hung out with the aforementioned guys).
One day I entered class, he and friends were already there, he says something stupid and insulting to me while I was starting a quick game of cards (we play Skat in germany ... card game of kings) and I flip him off.
He acts insulted, pulls himself up and marches over to me and grabs me by the front of my shirt to scare the holy terror out of me. Now, I am smaller than him, but I necessarily weak. I was good at sports and had some Judo lessons in the past, so I wasn't a stranger to physical confrontation either ... I just don't like confrontations - physical or otherwise.
Anyway, I grabbed his wrist firmly, looked at him and talked at him like "Go on, throw a punch. I'm just waiting for it." and wait I did. Eventually he released me with a disdainful laugh and got back to his friends, his mission of scaring me accomplished.
After that episode no one bothered to bother me like that.
I know that my situation won't translate well for everyone out there that gets bullied, but I think some lessons apply to most situations:
1. don't take their abuse forever. be prepared to eventually confront the bullys.
2. challenge them in a controlled environment of your own choosing. witnesses. don't let them choose the place.
3. preferably act after they visibly bullied you: they are the guilty ones!
4. give them a way out of physical confrontation. encourage it, actually, although not through begging. this creates the impression that you scared them away.
5. when they relent, give them as much face as you can. if you humiliate them too much, they'll choose the place for the next meeting.
6. don't be afraid of getting a few solid smacks in your face if your courage fails to impress them the first time. it smarts, but it will go away. it's a small price to pay for standing your ground.
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Hope that helps. Cheers!