Exclamation marking profound emotion. Commonly applied to situations involving:
1) Exasperation or stress
2) Near-orgasmic satisfaction with life
1) "Fucking orgo test tomorrow and I haven't even begun memorizing my hundred characters for Intensive Introduction to Chinese.... Holy shit, AND a paper on goddamned T.S. Elliot. Fuck my tits, Matt. Fuck my tits."
2) "OMG I just had Chipotle after three months of abstinence. Fuck my tits fuck my tits fuck my tits."