1. In celebration of a well formulated dis, specifically at the peak of misery for the person being dissed
2. When going around a corner at high speed
3. In celeberation of anything great
Note: The number of I's, R's, and T's used can vary from one to infinite.
"Ouch dude, you've hurt my feelings."
2. Garrett took the corner at 50 miles per hour, slingshotting his friends against the side of the car. "Skiiirrrttt!"
3. "Dude, we got tickets to see The Decemberists!"