TH

For me, TH means "The Heck" Make up your own excuse :)

Friend 1: Th! I just died for no reason!!
Friend 2: TH ME TOO!
Friend 1: This is the worst game in the universe.
Friend 2: New game?
Friend 1: New game. AND THIS TIME. I DON'T WANNA GO LIKE "TH" again.

Fu

Another way of saying, f*ck you.

Also used in the word "Kung Fu".

Person 1: Hey, I saw you making out with my girlfriend last night.

Person 2: Fu.