Go and suck my mums nipples??? That's awesome. Look kid, if you want to get into an insult match you will lose. That's fact.
As for the assumption that all 16 year olds carry knives, I know that is ***. Having worked in communitys on a voluntary basis providing support to 'wayward' kids I know that most kids are decent. However, I also know that if one of those kids started complaining about how much trouble he may get into cos he and his mates attacked an innocent man then I would tear him a new arrsehole.
I'm gonna answer another of your points. I wasn't bullied in school. In fact I quite enjoyed it. It was a good laugh. I don't think I'm 'big' cos I'm an adult. I think I'm big because the actions, decisions, roles and responsibilities I've had to make in life give me that right.
So, you're after advice. Well here's mine, tell your cousin to accept his punishment like a man, ensure that you never decide that it is acceptable to attack people for standing up on a bus, don't insult the people who you are asking for help.
Oh, and if you want to play with the big boys then make sure you're not still sucking your thumb!
Hope this helps. Laters loser!