Cali-Girl way of saying "Oh my god". Usually used in instances when something shocking or exciting.
Katy: So, did you hear that Jade is dating Wade?!
Selena: Eh Moi Gawd! That totally rhymes! Cute!
Literally translated from Russian means "end my suffering." It also sounds cool to say.
You: Prekratit moi stradaniya
Somebody else: the hell does that mean?
You: Nevermind.