G.I.T.S.
a fancy way to say you're getting lucky. It means you're about to get laid and it's not even slightly embarrassing.
Hey bro, you're G. I. T. S. tonight. That chick is yours.
Don't be shy, you're G. I. T. S. time. Just go for it.
You're G. I. T. S. and you know it. Don't act like you're not.