STFY

Meaning: Shit The Fuck Yeah
Used as an affirmative response or exclamation of excitement, happiness or otherwise heightened positive response

Person 1: Do you want to go skiing this weekend?
Person 2: STFY!

Scenario: A person pulls off a difficult trick, jump, or other stunt.

Response: STFY!

For maximum effect, STFY can be elongated to SHIT THE FUCK YEAH!!