Twite is not a word. It isnt even real slang. A couple of slow friends of mine thought that is what British people say as a statement of agreement. It does not mean ANYTHING and you sound like a complete ass when you use it.
Also, people might think you are calling them a twat. Another reason not to use it.
"Man that movie was sweet"
"...What the Hell did you call me"
"Nothing I just said twite!"
"STOP CALLING ME THAT"
"I hate you."