In motorcycle stunting, pulling a wheelie so high that the bike rests on the it's tail section is called a "twelve o'clock". The act thereof is called "twelving".
When you're with your group of friends and they all start cornering you by being annoying, twelving is the perfect word to use.
It was a play on words to mean annoying. Since 'twelve' in Korean is shipi (십이) and 'annoying' is shibi (시비), it was a clever way to combine the two for a whole new word. (Credits to Koreaboo)