I've got a question for you all! I'm not a very good pedant so please be gentle. 
When you shorten the word "sarcastic", would you shorten it to "sarcy" or "sarky"? In my mind, it's sarky because of the k noise and sarcy looks to me like it would be pronounced sarsy.
But what is the actual way to do it? I see sarcy everywhere and it's driving me to distraction.