The best way to irritate your brother, or sister.

Be extra nice to him all the time, no matter what. Smile at him for no apparent reason - not just your normal smile, but a slightly-manic, extra-wide smile. When he's out, tidy his room up, including dusting and vacuuming. He'll wonder what you're up to and go into paranoiac mode. If he snaps and pulls you up on your strange behaviour, deny that you're doing anything unusual but apologise and tell him that you'll be more careful in future. After that, be twice as nice to him if possible.

i'm 26 but i'm the youngest and the best thing i can do is keep my calm when they are shouting and asking for me to shout back. I answer calmly and with pause between the words in order for them to understand. works well and not only with brothers/sisters ;)

I am the youngest so I taught my kids ways to irritate each other. My favorite way is- Hold your finger about 3 or 4 inches from the person's face or arm or wherever and say, "I'm not touching you!" It really irks them. I love it when my youngest irritates her sister with that one.

Well, My brother really irritates me by getting in my space. bugging me while i'm trying to do something and just standing there and staring with this stupid grin on his face. drives mes up the wall! I don't really do much i don't think.. i don't really pay much attention because hes just always annoying me! lol but i can irritate him by taking my sweeeeeeeeet time going to fix something of his he needs help with like his xbox live or whatever. So I always get him back. Without me he can't work anything like that lol.. bwhahahaha