Santino is a verb, coined by myself and @erinscafe in highschool. It is derived from the name of another of our schoolmates, whose last name I won't tell you because now he's famous and working on Broadway and I'd rather not get sued.
To be santinoed means that you have said something funny or clever, perhaps linked to something cool on twitter. Then your louder, more popular friend repeats you, or retweets you without giving you any credit. Thereby effectively 'stealing your thunder' as it were.
Meanwhile, everyone tells your friend how awesome they are, and giving them all the credit while you just, you know...hang out.
