F7U12
Simply put, it's a shortened version of FFFFFFFUUUUUUUUUUUU. 7 F's and 12 U's. Any more than that and you're doing it wrong.
Waiter: What would you like to drink sir?
You: I'll have a coke, my good man. Shaken, not stirred.
Waiter: Dreadfully sorry my lord, we only have Pepsi.
You: ...
You: .....
You: F7U12 D:<
You: I'll have a coke, my good man. Shaken, not stirred.
Waiter: Dreadfully sorry my lord, we only have Pepsi.
You: ...
You: .....
You: F7U12 D:<